Ion exchangeable glass with high crack initiation threshold

ABSTRACT

Alkali aluminosilicate glasses that are resistant to damage due to sharp impact and capable of fast ion exchange are provided. The glasses comprise at least 4 mol % P 2 O 5  and, when ion exchanged, have a Vickers indentation crack initiation load of at least about 7 kgf.

This application claims the benefit of priority under 35 USC §119 ofU.S. Provisional Application Ser. No. 61/560,434 filed Nov. 16, 2011 thecontent of which is relied upon and incorporated herein by reference inits entirety.

BACKGROUND

The disclosure relates to damage resistant glasses. More particularly,the disclosure relates to damage resistant glasses that have optionallybeen strengthened by ion exchange. Even more particularly, thedisclosure relates to damage resistant, phosphate containing glassesthat have optionally been strengthened by ion exchange.

SUMMARY

Alkali aluminosilicate glasses which, when strengthened, are resistantto damage due to sharp impact and capable of fast ion exchange, areprovided. The glasses comprise at least 4 mol % P₂O₅ and, when ionexchanged, have a Vickers indentation crack initiation load of at leastabout 7 kgf.

Accordingly, one aspect comprises an alkali aluminosilicate glasscomprising at least about 4% P₂O₅, wherein the alkali aluminosilicateglass is ion exchanged to a depth of layer of at least about 10 μm, andwherein:

0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4; or  i.

1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3;  ii.

where M₂O₃═Al₂O₃+B₂O₃, R_(x)O is the sum of monovalent and divalentcation oxides present in the alkali aluminosilicate glass, and R₂O isthe sum of monovalent cation oxides present in the alkalialuminosilicate glass. In some embodiments, the glass satisfies0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4. In some embodiments, the glasssatisfies 0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1. In some embodiments, theglass satisfies 1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3. In some embodiments, theglass satisfies 1.5<[(P₂O₅+R₂O)/M₂O₃]≦2.0. In some embodiments, thealkali aluminosilicate glass further comprises less than 1 mol % K₂O. Insome embodiments, the alkali aluminosilicate glass further comprisesless than 1 mol % B₂O₃. In some embodiments, the monovalent and divalentcation oxides are selected from the group consisting of Li₂O, Na₂O, K₂O,Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO. In some embodiments, the alkalialuminosilicate glass has a potassium/sodium interdiffusion coefficientof at least about 2.4×10⁻¹⁰ cm²/s at 410° C. In some embodiments, thepotassium/sodium interdiffusion coefficient is in a range from about2.4×10⁻¹⁰ cm²/s up to about 1.5×10⁻⁹ cm²/s at 410° C. In someembodiments, the glass has a compressive layer extending from a surfaceof the glass to the depth of layer, and wherein the compressive layer isunder a compressive stress of at least about 300 MPa. In someembodiments, the glass has a Vickers indentation crack initiation loadof at least about 7 kgf. In some embodiments, the glass has a Vickersindentation crack initiation load of at least about 12 kgf.

Another aspect comprises an alkali aluminosilicate glass comprising fromabout 40 mol % to about 70 mol % SiO₂; from about 11 mol % to about 25mol % Al₂O₃; from about 4 mol % to about 15 mol % P₂O₅; and from about13 mol % to about 25 mol % Na₂O. In some embodiments, the alkalialuminosilicate glass comprises from about 50 mol % to about 65 mol %SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4 mol % toabout 10 mol % P₂O₅; and from about 14 mol % to about 20 mol % Na₂O. Insome embodiments, the alkali aluminosilicate glass further comprisesless than 1 mol % K₂O. In some embodiments, the alkali aluminosilicateglass further comprises less than 1 mol % B₂O₃. In some embodiments, themonovalent and divalent cation oxides are selected from the groupconsisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO.In some embodiments, the alkali aluminosilicate glass has apotassium/sodium interdiffusion coefficient of at least about 2.4×10⁻¹⁰cm²/s at 410° C. In some embodiments, the potassium/sodiuminterdiffusion coefficient is in a range from about 2.4×10⁻¹⁰ cm²/s upto about 1.5×10⁻⁹ cm²/s at 410° C. In some embodiments, the glass has acompressive layer extending from a surface of the glass to the depth oflayer, and wherein the compressive layer is under a compressive stressof at least about 300 MPa. In some embodiments, the glass has a Vickersindentation crack initiation load of at least about 7 kgf. In someembodiments, the glass has a Vickers indentation crack initiation loadof at least about 12 kgf.

Another aspect comprises a method of strengthening an alkalialuminosilicate glass, the method comprising providing the alkalialuminosilicate glass comprising at least about 4% P₂O₅, wherein:

0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4; or  i.

1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3;  ii.

where M₂O₃═Al₂O₃+B₂O₃, R_(x)O is the sum of monovalent and divalentcation oxides present in the alkali aluminosilicate glass, and R₂O isthe sum of divalent cation oxides present in the alkali aluminosilicateglass, and immersing the alkali aluminosilicate glass in an ion exchangebath for a time period of up to about 24 hours to form a compressivelayer extending from a surface of the alkali aluminosilicate glass to adepth of layer of at least 10 μm. In some embodiments, the glasssatisfies 0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4. In some embodiments, theglass satisfies 0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1. In some embodiments,the glass satisfies 1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3. In some embodiments, theglass satisfies 1.5<[(P₂O₅+R₂O)/M₂O₃]≦2.0. In some embodiments, thealkali aluminosilicate glass comprises less than 1 mol % K₂O. In someembodiments, the alkali aluminosilicate glass comprises less than 1 mol% B₂O₃. In some embodiments, the compressive layer is under acompressive stress of at least about 300 MPa. In some embodiments, theion exchanged glass has a Vickers indentation crack initiation load ofat least about 7 kgf. In some embodiments, the ion exchanged glass has aVickers indentation crack initiation load of at least about 12 kgf.

Another aspect comprises an alkali aluminosilicate glass comprising atleast about 4 mol % P₂O₅, wherein [M₂O₃ (mol %)/R_(x)O(mol %)]<1.4,where M₂O₃═Al₂O₃+B₂O₃ and R_(x)O is the sum of monovalent and divalentcation oxides present in the alkali aluminosilicate glass. In someembodiments, [M₂O₃ (mol %)/R_(x)O(mol %)]<1.2. In some embodiments,[M₂O₃ (mol %)/R_(x)O(mol %)]<1. In some embodiments, the monovalent anddivalent cation oxides are selected from the group consisting of Li₂O,Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO.

In some embodiments, the alkali aluminosilicate glass comprises fromabout 40 mol % to about 70 mol % SiO₂; from about 11 mol % to about 25mol % Al₂O₃; from about 4 mol % to about 15 mol % P₂O₅; and from about13 mol % to about 25 mol % Na₂O. In other embodiments, the alkalialuminosilicate glass comprises from about 50 mol % to about 65 mol %SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4 mol % toabout 10 mol % P₂O₅; and from about 14 mol % to about 20 mol % Na₂O.

In some embodiments, the composition further comprises less than 1 mol %K₂O. In some embodiments, the composition further comprises about 0 mol% K₂O. In some embodiments, the composition further comprises less than1 mol % B₂O₃. In some embodiments, the composition further comprisesabout 0 mol % B₂O₃.

Embodiments may be ion exchanged. In some embodiments, the glass is ionexchanged to a depth of layer of at least about 10 μm. In someembodiments, the glass is ion exchanged to a depth of layer of at leastabout 20 μm. In other embodiments, the glass is ion exchanged to a depthof layer of at least about 40 μm. In some embodiments, the alkalialuminosilicate glass has a compressive layer extending from a surfaceof the glass to the depth of layer, and wherein the compressive layer isunder a compressive stress of at least about 300 MPa. In otherembodiments, the alkali aluminosilicate glass has a compressive layerextending from a surface of the glass to the depth of layer, and whereinthe compressive layer is under a compressive stress of at least about500 MPa. In other embodiments, the alkali aluminosilicate glass has acompressive layer extending from a surface of the glass to the depth oflayer, and wherein the compressive layer is under a compressive stressof at least about 750 MPa. In some embodiments, the ion exchanged alkalialuminosilicate glass has a Vickers indentation crack initiation load ofat least about 7 kgf. In still other embodiments, the ion exchangedalkali aluminosilicate glass has a Vickers indentation crack initiationload of at least about 15 kgf. In other embodiments, the ion exchangedalkali aluminosilicate glass has a Vickers indentation crack initiationload of at least about 20 kgf. In some embodiments, the alkalialuminosilicate glass has a potassium/sodium interdiffusion coefficientof at least about 2.4×10⁻¹⁰ cm²/s at 410° C. In some embodiments, thepotassium/sodium interdiffusion coefficient is in a range from about2.4×10⁻¹⁰ cm²/s up to about 1.5×10⁻⁹ cm²/s at 410° C.

Another aspect is to provide an alkali aluminosilicate glass comprisingat least about 4 mol % P₂O₅. The alkali aluminosilicate glass is ionexchanged to a depth of layer of at least about 10 μm, wherein0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4, where M₂O₃═Al₂O₃+B₂O₃ and R_(x)O isthe sum of monovalent and divalent cation oxides present in the alkalialuminosilicate glass. In some embodiments, 0.6<[M₂O₃ (mol %)/R_(x)O(mol%)]<1.2. In some embodiments, 0.6<[M₂O₃ (mol %)/R_(x)O(mol %)]<1. Insome embodiments, 0.8<[M₂O₃ (mol %)/R_(x)O(mol %)]<1. In someembodiments, the monovalent and divalent cation oxides are selected fromthe group consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO,and ZnO.

In some embodiments, the alkali aluminosilicate glass comprises fromabout 40 mol % to about 70 mol % SiO₂; from about 11 mol % to about 25mol % Al₂O₃; from about 4 mol % to about 15 mol % P₂O₅; and from about13 mol % to about 25 mol % Na₂O. In other embodiments, the alkalialuminosilicate glass comprises from about 50 mol % to about 65 mol %SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4 mol % toabout 10 mol % P₂O₅; and from about 14 mol % to about 20 mol % Na₂O.

In some embodiments, the composition further comprises less than 1 mol %K₂O. In some embodiments, the composition further comprises about 0 mol% K₂O. In some embodiments, the composition further comprises less than1 mol % B₂O₃. In some embodiments, the composition further comprisesabout 0 mol % B₂O₃.

Embodiments of the aspect may be ion exchanged. In some embodiments, theglass is ion exchanged to a depth of layer of at least about 10 μm. Insome embodiments, the glass is ion exchanged to a depth of layer of atleast about 20 μm. In other embodiments, the glass is ion exchanged to adepth of layer of at least about 40 μm. In some embodiments, the alkalialuminosilicate glass has a compressive layer extending from a surfaceof the glass to the depth of layer, and wherein the compressive layer isunder a compressive stress of at least about 300 MPa. In otherembodiments, the alkali aluminosilicate glass has a compressive layerextending from a surface of the glass to the depth of layer, and whereinthe compressive layer is under a compressive stress of at least about500 MPa. In other embodiments, the alkali aluminosilicate glass has acompressive layer extending from a surface of the glass to the depth oflayer, and wherein the compressive layer is under a compressive stressof at least about 750 MPa. In some embodiments, the ion exchanged alkalialuminosilicate glass has a Vickers indentation crack initiation load ofat least about 7 kgf. In still other embodiments, the ion exchangedalkali aluminosilicate glass has a Vickers indentation crack initiationload of at least about 15 kgf. In other embodiments, the ion exchangedalkali aluminosilicate glass has a Vickers indentation crack initiationload of at least about 20 kgf. In some embodiments, the alkalialuminosilicate glass has a potassium/sodium interdiffusion coefficientof at least about 2.4×10⁻¹⁰ cm²/s at 410° C. In some embodiments, thepotassium/sodium interdiffusion coefficient is in a range from about2.4×10⁻¹⁰ cm²/s up to about 1.5×10⁻⁹ cm²/s at 410° C.

Another aspect of the disclosure is to provide a method of strengtheningan alkali aluminosilicate glass. The method comprises: providing thealkali aluminosilicate glass, the alkali aluminosilicate glasscomprising at least about 4 mol % P₂O₅, wherein:

0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4; or  i.

1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3;  ii.

where M₂O₃═Al₂O₃+B₂O₃, R_(x)O is the sum of monovalent and divalentcation oxides present in the alkali aluminosilicate glass, and R₂O isthe sum of divalent cation oxides present in the alkali aluminosilicateglass, and immersing the alkali aluminosilicate glass in an ion exchangebath for a time period of up to about 24 hours to form a compressivelayer extending from a surface of the alkali aluminosilicate glass to adepth of layer of at least 10 μm. In some embodiments, the glasssatisfies 0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4. In some embodiments, theglass satisfies 0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1. In some embodiments,the glass satisfies 1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3. In some embodiments, theglass satisfies 1.5<[(P₂O₅+R₂O)/M₂O₃]≦2.0. In some embodiments, thealkali aluminosilicate glass comprises less than 1 mol % K₂O. In someembodiments, the alkali aluminosilicate glass comprises less than 1 mol% B₂O₃. In some embodiments, the compressive layer is under acompressive stress of at least about 300 MPa. In some embodiments, theion exchanged glass has a Vickers indentation crack initiation load ofat least about 7 kgf. In some embodiments, the ion exchanged glass has aVickers indentation crack initiation load of at least about 12 kgf. Insome embodiments, the compressive layer extends from a surface to adepth of layer of at least 70 μm.

In some embodiments, the alkali aluminosilicate glass has a compressivelayer extending from a surface of the glass to the depth of layer, andwherein the compressive layer is under a compressive stress of at leastabout 300 MPa. In other embodiments, the alkali aluminosilicate glasshas a compressive layer extending from a surface of the glass to thedepth of layer, and wherein the compressive layer is under a compressivestress of at least about 500 MPa. In other embodiments, the alkalialuminosilicate glass has a compressive layer extending from a surfaceof the glass to the depth of layer, and wherein the compressive layer isunder a compressive stress of at least about 750 MPa. In someembodiments, the ion exchanged alkali aluminosilicate glass has aVickers indentation crack initiation load of at least about 7 kgf. Instill other embodiments, the ion exchanged alkali aluminosilicate glasshas a Vickers indentation crack initiation load of at least about 15kgf. In other embodiments, the ion exchanged alkali aluminosilicateglass has a Vickers indentation crack initiation load of at least about20 kgf. In some embodiments, the alkali aluminosilicate glass has apotassium/sodium interdiffusion coefficient of at least about 2.4×10⁻¹⁰cm²/s at 410° C. In some embodiments, the potassium/sodiuminterdiffusion coefficient is in a range from about 2.4×10⁻¹⁰ cm²/s upto about 1.5×10⁻⁹ cm²/s at 410° C.

In some embodiments, the alkali aluminosilicate glass used in the methodcomprises monovalent and divalent cation oxides selected from the groupconsisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO.

In some embodiments, the alkali aluminosilicate glass used in the methodcomprises from about 40 mol % to about 70 mol % SiO₂; from about 11 mol% to about 25 mol % Al₂O₃; from about 4 mol % to about 15 mol % P₂O₅;and from about 13 mol % to about 25 mol % Na₂O. In other embodiments,the alkali aluminosilicate glass used in the method comprises from about50 mol % to about 65 mol % SiO₂; from about 14 mol % to about 20 mol %Al₂O₃; from about 4 mol % to about 10 mol % P₂O₅; and from about 14 mol% to about 20 mol % Na₂O.

In some embodiments, the composition used in the method furthercomprises less than 1 mol % K₂O. In some embodiments, the compositionused in the method further comprises about 0 mol % K₂O. In someembodiments, the composition used in the method further comprises lessthan 1 mol % B₂O₃. In some embodiments, the composition used in themethod further comprises about 0 mol % B₂O₃.

These and other aspects, advantages, and salient features will becomeapparent from the following detailed description, the accompanyingdrawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a glass sheet strengthenedby ion exchange; and

FIG. 2 is a plot of depth of layer as a function of compressive stressfor 0.7 mm thick samples that were annealed at 700° C. and ion exchangedin a molten KNO₃ salt bath at 410° C.

DETAILED DESCRIPTION

Disclosed are materials, compounds, compositions, and components thatcan be used for, can be used in conjunction with, can be used inpreparation for, or are embodiments of the disclosed method andcompositions. These and other materials are disclosed herein, and it isunderstood that when combinations, subsets, interactions, groups, etc.of these materials are disclosed that while specific reference of eachvarious individual and collective combinations and permutation of thesecompounds may not be explicitly disclosed, each is specificallycontemplated and described herein.

Thus, if a class of substituents A, B, and C are disclosed as well as aclass of substituents D, E, and F, and an example of a combinationembodiment, A-D is disclosed, then each is individually and collectivelycontemplated. Thus, in this example, each of the combinations A-E, A-F,B-D, B-E, B-F, C-D, C-E, and C-F are specifically contemplated andshould be considered disclosed from disclosure of A, B, and/or C; D, E,and/or F; and the example combination A-D. Likewise, any subset orcombination of these is also specifically contemplated and disclosed.Thus, for example, the sub-group of A-E, B-F, and C-E are specificallycontemplated and should be considered disclosed from disclosure of A, B,and/or C; D, E, and/or F; and the example combination A-D. This conceptapplies to all aspects of this disclosure including, but not limited toany components of the compositions and steps in methods of making andusing the disclosed compositions. Thus, if there are a variety ofadditional steps that can be performed it is understood that each ofthese additional steps can be performed with any specific embodiment orcombination of embodiments of the disclosed methods, and that each suchcombination is specifically contemplated and should be considereddisclosed.

In addition, whenever a group is described as comprising at least one ofa group of elements and combinations thereof, it is understood that thegroup may comprise, consist essentially of, or consist of any number ofthose elements recited, either individually or in combination with eachother. Similarly, whenever a group is described as consisting of atleast one of a group of elements or combinations thereof, it isunderstood that the group may consist of any number of those elementsrecited, either individually or in combination with each other.

Moreover, where a range of numerical values is recited herein,comprising upper and lower values, unless otherwise stated in specificcircumstances, the range is intended to include the endpoints thereof,and all integers and fractions within the range. It is not intended thatthe scope of the disclosure be limited to the specific values recitedwhen defining a range. Further, when an amount, concentration, or othervalue or parameter is given as a range, one or more preferred ranges ora list of upper preferable values and lower preferable values, this isto be understood as specifically disclosing all ranges formed from anypair of any upper range limit or preferred value and any lower rangelimit or preferred value, regardless of whether such pairs areseparately disclosed. Finally, when the term “about” is used indescribing a value or an end-point of a range, the disclosure should beunderstood to include the specific value or end-point referred to.

As used herein, the term “about” means that amounts, sizes,formulations, parameters, and other quantities and characteristics arenot and need not be exact, but may be approximate and/or larger orsmaller, as desired, reflecting tolerances, conversion factors, roundingoff, measurement error and the like, and other factors known to those ofskill in the art. In general, an amount, size, formulation, parameter orother quantity or characteristic is “about” or “approximate” whether ornot expressly stated to be such.

The term “or”, as used herein, is inclusive; more specifically, thephrase “A or B” means “A, B, or both A and B”. Exclusive “or” isdesignated herein by terms such as “either A or B” and “one of A or B”,for example.

The indefinite articles “a” and “an” are employed to describe elementsand components of embodiments. The use of these articles means that oneor at least one of these elements or components is present. Althoughthese articles are conventionally employed to signify that the modifiednoun is a singular noun, as used herein the articles “a” and “an” alsoinclude the plural, unless otherwise stated in specific instances.Similarly, the definite article “the”, as used herein, also signifiesthat the modified noun may be singular or plural, again unless otherwisestated in specific instances.

For the purposes of describing the embodiments, it is noted thatreference herein to a variable being a “function” of a parameter oranother variable is not intended to denote that the variable isexclusively a function of the listed parameter or variable. Rather,reference herein to a variable that is a “function” of a listedparameter is intended to be open ended such that the variable may be afunction of a single parameter or a plurality of parameters. It is alsounderstood that, unless otherwise specified, terms such as “top,”“bottom,” “outward,” “inward,” and the like are words of convenience andare not to be construed as limiting terms.

It is noted that terms like “preferably,” “commonly,” and “typically,”when utilized herein, are not utilized to limit the scope or to implythat certain features are critical, essential, or even important to thestructure or function of the embodiments described. Rather, these termsare merely intended to identify particular aspects of an embodiment orto emphasize alternative or additional features that may or may not beutilized in a particular embodiment.

For the purposes of describing and defining embodiments it is noted thatthe terms “substantially” and “approximately” are utilized herein torepresent the inherent degree of uncertainty that may be attributed toany quantitative comparison, value, measurement, or otherrepresentation. The terms “substantially” and “approximately” are alsoutilized herein to represent the degree by which a quantitativerepresentation may vary from a stated reference without resulting in achange in the basic function of the subject matter at issue.

It is noted that one or more of the claims may utilize the term“wherein” as a transitional phrase. For the purposes of definingembodiments, it is noted that this term is introduced in the claims asan open-ended transitional phrase that is used to introduce a recitationof a series of characteristics of the structure and should beinterpreted in like manner as the more commonly used open-ended preambleterm “comprising.”

As a result of the raw materials and/or equipment used to produce theglass composition, certain impurities or components that are notintentionally added, can be present in the final glass composition. Suchmaterials are present in the glass composition in minor amounts and arereferred to herein as “tramp materials.”

As used herein, a glass composition having 0 wt % or mol % of a compoundis defined as meaning that the compound, molecule, or element was notpurposefully added to the composition, but the composition may stillcomprise the compound, typically in tramp or trace amounts. Similarly,“sodium-free,” “alkali-free,” “potassium-free” or the like are definedto mean that the compound, molecule, or element was not purposefullyadded to the composition, but the composition may still comprise sodium,alkali, or potassium, but in approximately tramp or trace amounts.Unless otherwise specified, the concentrations of all constituentsrecited herein are expressed in terms of mole percent (mol %).

Vickers indentation cracking threshold measurements described herein areperformed by applying and then removing an indentation load to the glasssurface at a rate of 0.2 mm/min. The maximum indentation load is heldfor 10 seconds. The indentation cracking threshold is defined at theindentation load at which 50% of 10 indents exhibit any number ofradial/median cracks emanating from the corners of the indentimpression. The maximum load is increased until the threshold is met fora given glass composition. All indentation measurements are performed atroom temperature in 50% relative humidity.

Referring to the drawings in general and to FIG. 1 in particular, itwill be understood that the illustrations are for the purpose ofdescribing particular embodiments and are not intended to limit thedisclosure or appended claims thereto. The drawings are not necessarilyto scale, and certain features and certain views of the drawings may beshown exaggerated in scale or in schematic in the interest of clarityand conciseness.

Chemically strengthened alkali aluminosilicate glasses having highdamage resistance (i.e., having Vickers cracking thresholds of greaterthan 15 kilograms force (kgf), and, in some embodiments, greater than 20kgf, typically have compositions that satisfy the rule [(Al₂O₃(mol%)+B₂O₃(mol %))/(Σmodifier oxides(mol %))]>1, where the modifier oxidesinclude alkali and alkaline earth oxides. Such glasses have beenpreviously described in U.S. patent application Ser. No. 12/858,490,filed Aug. 18, 2010, by Kristen L. Barefoot et al., entitled “Crack andScratch Resistant Glass and Enclosures Made Therefrom.”

The enhanced damage resistance of P₂O₅-containing alkali aluminosilicateglasses has been previously described in U.S. Provisional PatentApplication No. 61/417,941, filed on Nov. 30, 2010, by Dana CraigBookbinder et al., entitled “Ion Exchangeable Glass with DeepCompressive Layer and High Modulus.” The glasses described thereincontain phosphate batched with Al₂O₃ and B₂O₃ to form AlPO₄ and BPO₄,respectively, and follow the composition rule

0.75≦[(P₂O₅(mol%)+R₂O(mol%))/M₂O₃(mol%)]≦1.3,

where M₂O₃═Al₂O₃+B₂O₃.

Described herein are embodiments comprising P₂O₅-containing alkalialuminosilicate glasses and articles made therefrom which, whenchemically strengthened by ion exchange, achieve Vickers crackingthresholds of at least about 7 kgf, 8, kgf, 9, kgf, 10, kgf, 11 kgf, 12kgf, 13 kgf, 14 kgf, 15 kgf 16 kgf, 17 kgf, 18 kgf, 19 kgf, and, in someembodiments, at least about 20 kgf. The damage resistance of theseglasses and glass articles is enhanced by the addition of at least about4 mol % P₂O₅. In some embodiments, the damage resistance is enhanced bythe addition of at least about 5 mol % P₂O₅. In some embodiments, theP₂O₅ concentration is in a range from about 4 mol % up to about 10 mol %and, in other embodiments in a range from about 4 mol % up to about 15mol %.

Embodiments described herein generally fall outside the glasses andglass articles of the composition space described in U.S. ProvisionalPatent Application No. 61/417,941. In addition, the glasses described inthe present disclosure nominally comprise primarily tetrahedrallycoordinated phosphate (PO₄ ³⁻) groups that contain one double-bondedoxygen per tetrahedral phosphorus structural unit.

In some embodiments, ratios of M₂O₃ to ΣR_(x)O provide glasses that haveadvantageous melting temperatures, viscosities, and/or liquidustemperatures. Some embodiments may be described by the ratio (M₂O₃(mol%)/ΣR_(x)O(mol %))<1.4, where M₂O₃═Al₂O₃+B₂O₃, and wherein ΣR_(x)O isthe sum of monovalent and divalent cation oxides present in the alkalialuminosilicate glass. In some embodiments, the glasses and glassarticles described herein comprise greater than 4 mol % P₂O₅, whereinthe ratio (M₂O₃(mol %)/ΣR_(x)O(mol %)) is less than 1.4, whereM₂O₃═Al₂O₃+B₂O₃, and wherein ΣR_(x)O is the sum of monovalent anddivalent cation oxides present in the alkali aluminosilicate glass. Insome embodiments, the ratio of (M₂O₃(mol %)/ΣR_(x)O(mol %)) is less than1.0. In some embodiments, the ratio of (M₂O₃(mol %)/ΣR_(x)O(mol %)) isless than 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.1, 1.05, 1.0, 0.95, 0.9,0.85, 0.8, 0.75, or 0.7. In some embodiments, 0.6<(M₂O₃(mol%)/R_(x)O(mol %))<1.4. In some embodiments, 0.6<(M₂O₃(mol %)/R_(x)O(mol%))<1.2. In some embodiments, 0.6<(M₂O₃(mol %)/R_(x)O(mol %))<1. In someembodiments, 0.8<(M₂O₃(mol %)/R_(x)O(mol %))<1.4. In some embodiments,0.8<(M₂O₃(mol %)/R_(x)O(mol %))<1.2. In some embodiments, 0.8<(M₂O₃(mol%)/R_(x)O(mol %))<1.0. In some embodiments, Y<(M₂O₃(mol %)/R_(x)O(mol%))<Z, wherein Y is about 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95,1.0, 1.05, or 1.1 and X is independently about 1.4, 1.35, 1.3, 1.25,1.2, 1.15, 1.1, 1.05, 1.0, 0.95, 0.9, 0.85, 0.8, and wherein X>Y. Suchmonovalent and divalent oxides include, but are not limited to, alkalimetal oxides (Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O), alkaline earth oxides (MgO,CaO, SrO, BaO), and transition metal oxides such as, but not limited to,ZnO.

In some embodiments, the glasses described herein satisfy the inequality

[(Al₂O₃(mol%)+B₂O₃(mol%))/(Σmodifier oxides(mol%))]<1.0.

In some embodiments, the glasses can have sufficient P₂O₅ to allow for aglass structure wherein P₂O₅ is present in the structure rather, or inaddition to, MPO₄. In some embodiments, such a structure may bedescribed by the ratio [(P₂O₅ (mol %)+R₂O (mol %))/M₂O₃ (mol %)]>1.24,where M₂O₃═Al₂O₃+B₂O₃, P₂O₅ is 4 mol % or greater, and wherein R₂O isthe sum divalent cation oxides present in the alkali aluminosilicateglass. In some embodiments, the glasses described herein comprisegreater than 4 mol % P₂O₅, wherein the ratio of [(P₂O₅(mol %)+R₂O (mol%))/M₂O₃ (mol %)] is greater than 1.24, where M₂O₃═Al₂O₃+B₂O₃, andwherein R₂O is the sum divalent cation oxides present in the alkalialuminosilicate glass. In some embodiments, the ratio of [(P₂O₅(mol%)+R₂O (mol %))/M₂O₃ (mol %)] is greater than 1.3. In some embodiments,the ratio is 1.24≦[(P₂O₅(mol %)+R₂O (mol %))/M₂O₃ (mol %)]≦2.8. In someembodiments, the glasses and glass articles described herein comprisegreater than 4 mol % P₂O₅, and are described by the ratio

S≦[(P₂O₅(mol%)+R₂O(mol%))/M₂O₃(mol%)]≦V

wherein S is independently about 1.5, 1.45, 1.4, 1.35, 1.3, 1.25, 1.24,1.2, or 1.15, and V is independently about 2.0, 2.05, 2.1, 2.15, 2.2,2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, or 2.8.

The alkli aluminosilicate glasses and articles described herein comprisea number of chemical components. SiO₂, an oxide involved in theformation of glass, functions to stabilize the networking structure ofglass. In some embodiments, the glass composition can comprise fromabout 40 to about 70 mol % SiO₂. In some embodiments, the glasscomposition can comprise from about 50 to about 70 mol % SiO₂. In someembodiments, the glass composition can comprise from about 55 to about65 mol % SiO₂. In some embodiments, the glass composition can comprisefrom about 40 to about 70 mol %, about 40 to about 65 mol %, about 40 toabout 60 mol %, about 40 to about 55 mol %, about 40 to 50 mol %, about40 to 45 mol %, 50 to about 70 mol %, about 50 to about 65 mol %, about50 to about 60 mol %, about 50 to about 55 mol %, about 55 to about 70mol %, about 60 to about 70 mol %, about 65 to about 70 mol %, about 55to about 65 mol %, or about 55 to about 60 mol % SiO₂. In someembodiments, the glass composition comprises about 40, 41, 42, 43, 44,45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,63, 64, 65, 66, 67, 68, 69, or 70 mol % SiO₂.

Al₂O₃ may provide, among other benefits, for a) maintaining the lowestpossible liquidus temperature, b) lowering the expansion coefficient, orc) enhancing the strain point. In some embodiments, the glasscomposition can comprise from about 11 to about 25 mol % Al₂O₃. In someembodiments, the glass composition can comprise from about 14 to about20 mol % Al₂O₃. In some embodiments, the glass composition can comprisefrom about 11 to about 25 mol %, about 11 to about 20 mol %, about 11 toabout 18 mol %, about 11 to about 15 mol %, about 12 to about 25 mol %,about 12 to about 20 mol %, about 12 to about 18 mol %, about 12 toabout 15 mol %, about 14 to about 25 mol %, about 14 to about 20 mol %,about 14 to about 18 mol %, about 14 to about 15 mol %, about 18 toabout 25 mol %, about 18 to about 20 mol %, or about 20 to about 25 mol% Al₂O₃. In some embodiments, the glass composition can comprise about11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 mol %Al₂O₃.

The presence of B₂O₃ in embodiments can improve damage resistance, butmay also be detrimental to compressive stress and diffusivity. Theglasses described herein generally do not contain—or are free of—B₂O₃.In some embodiments, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,1, 2, 3, or 4 mol % B₂O₃ may be present. In some embodiments, less than4, 3, 2, or 1 mol % B₂O₃ may be present. In some embodiments, tramp B₂O₃may be present. In some embodiments, the glass composition can compriseabout 0 mol % B₂O₃. In some embodiments, the amount of B₂O₃ is 0.5 mol %or less, 0.25 mol % or less, 0.1 mol % or less, about 0.05 mol % orless, 0.001 mol % or less, 0.0005 mol % or less, or 0.0001 mol % orless. The glass compositions, according to some embodiments, are free ofintentionally added B₂O₃.

It has been discovered that addition of phosphorous to the glass as P₂O₅improves damage resistance and does not impede ion exchange. In someembodiments, the addition of phosphorous to the glass creates astructure in which silica (SiO₂ in the glass) is replaced by aluminumphosphate (AlPO₄), which consists of tetrahedrally coordinated aluminumand phosphorus and/or boron phosphate (BPO₄), which consists oftetrahedrally coordinated boron and phosphorus. The glasses describedherein generally contain greater than 4 mol % P₂O₅. In some embodiments,the glass can comprise from about 4 to about 15 mol % P₂O₅. In someembodiments, the glass can comprise from about 4 to about 12 mol % P₂O₅.In some embodiments, the glass can comprise from about 4 to about 10 mol% P₂O₅. In some embodiments, the glass can comprise from about 6 toabout 10 mol % P₂O₅. In some embodiments, the glass composition cancomprise from about 4 to about 15 mol %, about 6 to about 15 mol %,about 8 to about 15 mol %, about 10 to about 15 mol %, about 12 to about15 mol %, about 4 to about 12 mol %, about 4 to about 10 mol %, about 4to about 8 mol %, about 4 to about 6 mol %, about 6 to about 12 mol %,about 6 to about 10 mol %, about 6 to about 8 mol %, about 8 to about 12mol %, about 8 to about 10 mol %, about 10 to about 12 mol %. In someembodiments, the glass composition can comprise about 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, or mol % P₂O₅.

Na₂O may be used for ion exchange in embodied glasses. In someembodiments, the glass can comprise from about 13 to about 25 mol %Na₂O. In other embodiments, the glass can comprise about 13 to about 20mol % Na₂O. In some embodiments, the glass composition can comprise fromabout 13 to about 25 mol %, about 13 to about 20 mol %, about 13 toabout 18 mol %, about 13 to about 15 mol %, about 15 to about 25 mol %,about 15 to about 20 mol %, about 15 to about 18 mol %, about 18 toabout 25 mol %, about 18 to about 20 mol %, or about 20 to about 25 mol%. In some embodiments, the glass can comprise about 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, or 25 mol % Na₂O.

R_(x)O generally describes monovalent and divalent cation oxides presentin the alkali aluminosilicate glass. The presence R_(x)O may provideadvantages for ion exchange of the glass. Such monovalent and divalentoxides include, but are not limited to, alkali metal oxides (Li₂O, Na₂O,K₂O, Rb₂O, Cs₂O), alkaline earth oxides (MgO, CaO, SrO, BaO), andtransition metal oxides such as, but not limited to, ZnO. In someembodiments, the amount of R_(x)O in the composition is described by theequation (M₂O₃(mol %)/ΣR_(x)O(mol %))<1.4. In some embodiments, theamount of R_(x)O in the composition is described by the equation(M₂O₃(mol %)/ΣR_(x)O(mol %))<1.0. In some embodiments, the amount ofR_(x)O in the composition is described by the equation 0.6<(M₂O₃(mol%)/ΣR_(x)O(mol %))<1.4. In some embodiments, the amount of R_(x)O in thecomposition is described by the equation 0.6<(M₂O₃(mol %)/ΣR_(x)O(mol%))<1.0. In some embodiments, the glass composition can comprise fromabout 7 to about 30 mol % Al₂O₃. In some embodiments, the glasscomposition can comprise from about 14 to about 25 mol % Al₂O₃. In someembodiments, the glass composition can comprise from about 7 to about 30mol %, about 7 to about 25 mol %, about 7 to about 22 mol %, about 7 toabout 20 mol %, about 7 to about 18 mol %, about 7 to about 15 mol %,about 7 to about 10 mol %, about 10 to about 30 mol %, about 10 to about25 mol %, about 10 to about 22 mol %, about 10 to about 18 mol %, about10 to about 15 mol %, about 15 to about 30 mol %, about 15 to about 25mol %, about 15 to about 22 mol %, about 15 to about 18 mol %, about 18to about 30 mol %, about 18 to about 25 mol %, about 18 to about 22 mol%, about 18 to about 20 mol %, about 20 to about 30 mol %, about 20 toabout 25 mol %, about 20 to about 22 mol %, about 22 to about 30 mol %,about 22 to about 25 mol %, or about 25 to about 30 mol %. In someembodiments, the glass composition can comprise about 8, 9, 10, 11, 12,13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or30 mol % R_(x)O.

M₂O₃ describes the amount of Al₂O₃ and B₂O₃ in the composition. In someembodiments, the glass composition can comprise from about 11 to about30 mol % M₂O₃. In some embodiments, the glass composition can comprisefrom about 14 to about 20 mol % M₂O₃. In some embodiments, the glasscomposition can comprise from about 11 to about 30 mol %, about 11 toabout 25 mol %, about 11 to about 20 mol %, about 11 to about 18 mol %,about 11 to about 15 mol %, about 12 to about 30 mol %, about 12 toabout 25 mol %, about 12 to about 20 mol %, about 12 to about 18 mol %,about 12 to about 15 mol %, about 14 to about 30 mol %, about 14 toabout 25 mol %, about 14 to about 20 mol %, about 14 to about 18 mol %,about 14 to about 15 mol %, about 18 to about 25 mol %, about 18 toabout 20 mol %, or about 20 to about 25 mol % M₂O₃. In some embodiments,the glass composition can comprise about 11, 12, 13, 14, 15, 16, 17, 18,19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 mol % M₂O₃.

K₂O in some embodiments can be used for ion exchange, but can bedetrimental to compressive stress. In some embodiments, the glasscompositions are free of K₂O. The glass compositions are substantiallyK₂O-free, for example, when the content of K₂O is 0.5 mol percent orless, 0.25 mol % or less, 0.1 mol % or less, about 0.05 mol % or less,0.001 mol % or less, 0.0005 mol % or less, or 0.0001 mol % or less. Theglass sheets, according to some embodiments, are free of intentionallyadded sodium. In some embodiments, the glass can comprise from 0 toabout 1 mol % K₂O. In other embodiments, the glass can comprise greaterthan 0 to about 1 mol % K₂O. In some embodiments, the glass compositioncan comprise from 0 to about 2 mol %, 0 to about 1.5 mol %, 0 to about 1mol %, 0 to about 0.9 mol %, 0 to about 0.8 mol % 0 to about 0.7 mol %,0 to about 0.6 mol %, 0 to about 0.5 mol %, 0 to about 0.4 mol %, 0 toabout 0.3 mol %, 0 to about 0.2 mol %, or 0 to about 0.1 mol %. In someembodiments, the glass can comprise about 0, 0.01, 0.02, 0.03, 0.04,0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,0.9, or 1 mol % K₂O.

Additional components can be incorporated into the glass compositions toprovide additional benefits. For example, additional components can beadded as fining agents (e.g., to facilitate removal of gaseousinclusions from melted batch materials used to produce the glass) and/orfor other purposes. In some embodiments, the glass may comprise one ormore compounds useful as ultraviolet radiation absorbers. In someembodiments, the glass can comprise 3 mol % or less TiO₂, MnO, ZnO,Nb₂O₅, MoO₃, Ta₂O₅, WO₃, ZrO₂, Y₂O₃, La₂O₃, HfO₂, CdO, SnO₂, Fe₂O₃,CeO₂, As₂O₃, Sb₂O₃, Cl, Br, or combinations thereof. In someembodiments, the glass can comprise from 0 to about 3 mol %, 0 to about2 mol %, 0 to about 1 mol %, 0 to 0.5 mol %, 0 to 0.1 mol %, 0 to 0.05mol %, or 0 to 0.01 mol % TiO₂, MnO, ZnO, Nb₂O₅, MoO₃, Ta₂O₅, WO₃, ZrO₂,Y₂O₃, La₂O₃, HfO₂, CdO, SnO₂, Fe₂O₃, CeO₂, As₂O₃, Sb₂O₃, Cl, Br, orcombinations thereof. In some embodiments, the glass can comprise from 0to about 3 mol %, 0 to about 2 mol %, 0 to about 1 mol %, 0 to about 0.5mol %, 0 to about 0.1 mol %, 0 to about 0.05 mol %, or 0 to about 0.01mol % TiO₂, CeO₂, or Fe₂O₃, or combinations thereof.

The glass composition, according to some embodiments, (e.g., any of theglasses discussed above) can include F, Cl, or Br, for example, as inthe case where the glasses comprise Cl and/or Br as fining agents.

The glass composition, according to some embodiments, can comprise BaO.In certain embodiments, the glasses can comprise less than about 5, lessthan about 4, less than about 3, less than about 2, less than about 1,less than 0.5, or less than 0.1 mol % of BaO.

In some embodiments, the glass can be substantially free of Sb₂O₃,As₂O₃, or combinations thereof. For example, the glass can comprise 0.05mol % or less of Sb₂O₃ or As₂O₃ or a combination thereof, the glass maycomprise zero mol % of Sb₂O₃ or As₂O₃ or a combination thereof, or theglass may be, for example, free of any intentionally added Sb₂O₃, As₂O₃,or combinations thereof.

The glasses, according to some embodiments, can further comprisecontaminants typically found in commercially-prepared glass. Inaddition, or alternatively, a variety of other oxides (e.g., TiO₂, MnO,ZnO, Nb₂O₅, MoO₃, Ta₂O₅, WO₃, ZrO₂, Y₂O₃, La₂O₃, P₂O₅, and the like) maybe added, albeit with adjustments to other glass components, withoutcompromising the melting or forming characteristics of the glasscomposition. In those cases where the glasses, according to someembodiments, further include such other oxide(s), each of such otheroxides are typically present in an amount not exceeding about 3 mol %,about 2 mol %, or about 1 mol %, and their total combined concentrationis typically less than or equal to about 5 mol %, about 4 mol %, about 3mol %, about 2 mol %, or about 1 mol %. In some circumstances, higheramounts can be used so long as the amounts used do not place thecomposition outside of the ranges described above. The glasses,according to some embodiments, can also include various contaminantsassociated with batch materials and/or introduced into the glass by themelting, fining, and/or forming equipment used to produce the glass(e.g., ZrO₂).

In some embodiments, the alkali aluminosilicate glasses and articlesdescribed herein comprise from about 40 mol % to about 70 mol % SiO₂;from about 11 mol % to about 25 mol % Al₂O₃; from about 4 mol % to about15 mol % P₂O₅; and from about 11 mol % to about 25 mol % Na₂O.

In some embodiments, the glass compositions have high damage resistance.In some embodiments, the glass compositions have Vickers crackingthresholds of greater than 7 kilograms force (kgf). In some embodiments,the glass compositions have Vickers cracking thresholds of greater than12 kgf. In some embodiments, the glass compositions have Vickerscracking thresholds of greater than 15 kgf. In some embodiments, theglass compositions have Vickers cracking thresholds of greater than 20kgf. In some embodiments, the glass compositions have Vickers crackingthresholds of greater than 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, or 25 kgf.

Non-limiting examples of embodied glasses (wherein the glass thicknessis 0.7 mm) are listed in Table 1.

TABLE 1 Glass compositions and properties. Sample a b c d e f g h i j kl SiO₂ (mol %) 61 59 57 62 60 58 60 60 60 60 60 60 B₂O₃ (mol %) 0 0 0 00 0 0 0 0 0 0 0 Al₂O₃ (mol %) 15.5 16.5 17.5 15.5 16.5 17.5 16 16 16 1616 16 P₂O₅ (mol %) 7 7 7 6 6 6 5 5 6 6 7 7 Na₂O (mol %) 16.5 17.5 18.516.5 17.5 18.5 16 16 16 16 16 16 MgO (mol %) 0 0 0 0 0 0 3 0 2 0 1 0 ZnO(mol %) 0 0 0 0 0 0 0 3 0 2 0 1 Density 2.388 2.401 2.412 2.393 2.4062.416 (g/cm³) Molar Volume 30.41 30.43 30.47 30.01 30.03 30.08 (cm³/mol)Strain Point 615 620 625 633 638 640 (° C.) Anneal Point 675 678 682 693697 699 (° C.) Softening 963 958 951 973 978 969 Point (° C.) T200P (°C.) 1732 1708 1683 1752 1720 1698 T35000P (° C.) 1284 1274 1260 13041289 1275 T160000P (° C.) 1195 1186 1176 1215 1202 1191 Liquidus 775 740730 770 790 770 Temperature (° C.) 0.7 mm thick parts annealed 410° C.,8 hr 665 over over over over over Compressive limits limits limitslimits limits Stress (MPa) of of of of of FSM FSM FSM FSM FSM 410° C., 8hr 113 over over over over over Depth of Layer limits limits limitslimits limits (μm) of of of of of FSM FSM FSM FSM FSM 410° C., 1 hr 764806 866 805 863 922 Compressive Stress (MPa) 410° C., 1 hr 40 38 38 3937 36 Depth of Layer (μm) 410° C., 4 hr 706 747 804 745 805 overCompressive limits Stress (MPa) of FSM 410° C., 4 hr 80 82 80 77 77 overDepth of Layer limits (microns) of FSM 410° C., 4hr >25 >20 >20 >15 >25 >15 Vickers Crack Initiation Load (kgf) 470° C.,6 min 736 780 837 778 836 894 Compressive Stress (MPa) 470° C., 6 min 2323 23 23 23 23 Depth of Layer (μm) (Al₂O₃ + 0.94 0.94 0.95 0.94 0.940.95 0.84 0.84 0.89 0.89 0.94 0.94 B₂O₃)/R_(x)O (P₂O₅ + R_(x)O)/ 1.521.48 1.46 1.45 1.42 1.40 1.5 1.5 1.5 1.5 1.54 1.5 M₂O₃ K⁺/Na⁺ Ion- 5.785.65 5.50 5.43 5.16 4.69 Exchange Interdiffusion Coefficient at 410° C.in annealed parts × 10⁻¹⁰ (cm²/s)

Non-limiting examples of embodied glasses (wherein the glass thicknessis 1.0 mm) are listed in Table 2 (for ion-exchange data, if no SOC isprovided, the default used was 3.0 using 1.0 mm thick ion-exchangedparts).

TABLE 2 Glass compositions and properties. Example Number 1 2 3 4 5 6 7SiO₂ in mol % 61.0 59.0 57.0 62.0 60.0 58.0 58.0 Al₂O₃ in mol % 15.516.5 17.5 15.5 16.5 17.5 17.4 P₂O₅ in mol % 7.0 7.0 7.0 6.0 6.0 6.0 6.1Na₂O in mol % 16.5 17.5 18.5 16.5 17.5 18.5 18.5 MgO in mol % 0.0 0.00.0 0.0 0.0 0.0 0.1 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol% 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CaO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0(M₂O₃)/R_(x)O in mol % 0.94 0.94 0.95 0.94 0.94 0.95 0.95 (P₂O₅ +R₂O)/(M₂O₃) 1.52 1.48 1.46 1.45 1.42 1.40 1.41 in mol % (P₂O₅ +R_(x)O)/(M₂O₃) 1.52 1.48 1.46 1.45 1.42 1.40 1.40 in mol % SiO₂ in wt %50.5 48.5 46.6 51.9 49.9 48.0 48.0 Al₂O₃ in wt % 21.8 23.0 24.3 22.023.3 24.6 24.4 P₂O₅ in wt % 13.7 13.6 13.5 11.9 11.8 11.7 11.8 Na₂O inwt % 14.1 14.8 15.6 14.2 15.0 15.8 15.8 MgO in wt % 0.0 0.0 0.0 0.0 0.00.0 0.0 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.0 0.0 0.00.0 0.0 0.0 0.0 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Compositionalnone none none none none none XRF analysis Density (g/cm³) 2.388 2.4012.412 2.393 2.406 2.416 2.416 Molar Volume 30.41 30.43 30.47 30.01 30.0330.08 30.08 (cm³/mol) Strain Pt. (° C.) 615 620 625 633 638 640 640Anneal Pt. (° C.) 675 678 682 693 697 699 699 Softening Pt. (° C.) 963958 951 973 978 969 969 Temperature at 200 P 1732 1708 1683 1752 17201698 1698 Viscosity (° C.) Temperature at 35 kP 1284 1274 1260 1304 12891275 1275 Viscosity (° C.) Temperature at 160 1195 1186 1176 1215 12021191 1191 kP Viscosity (° C.) Liquidus 775 740 730 770 790 770 890Temperature (° C.) Liquidus Viscosity 2.91E+10 8.74E+10 4.40E+111.67E+11 2.46E+10 2.04E+11 7.09E+08 (P) Zircon Breakdown Temperature (°C.) Zircon Breakdown Viscosity (P) Stress Optical Coefficient ((nm ·Mpa⁻¹ · mm⁻¹) Approximate Fictive 675 678 682 693 697 699 795temperature (° C.) 410° C. 1 hr 777 820 881 819 878 938 804 CompressiveStress (MPa) 410° C. 1 hr Depth of 40 38 38 39 37 36 43 Layer (mm) 410°C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr CompressiveStress (MPa) 410° C. 2 hr Depth of Layer (mm) 410° C. 2 hr Vickers CrackInitiation Load (kgf) 410° C. 3 hr Compressive Stress (MPa) 410° C. 3 hrDepth of Layer (mm) 410° C. 4 hr 718 760 818 758 819 over CompressiveStress (MPa) 410° C. 4 hr Depth of 80 82 80 77 77 over Layer (mm) 410°C. 4 hr Vickers >25 >20 >20 >15 >25 >15 Crack Initiation Load (kgf) 410°C. 8 hr 678 over over over over over Compressive Stress (MPa) 410° C. 8hr Depth of 113 over over over over over Layer (mm) D FSM DOL  5.7E−10 5.1E−10  5.1E−10  5.4E−10  4.9E−10  4.6E−10  6.6E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL  5.7E−10  6.0E−10 5.7E−10  5.3E−10  5.3E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at410° C. 4 hr D FSM DOL  5.7E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5at 410° C. 8 hr Example Number 8 9 10 11 12 13 14 SiO₂ in mol % 60.060.0 60.0 60.0 60.0 60.0 62.0 Al₂O₃ in mol % 16.0 16.0 16.0 16.0 16.016.0 15.0 P₂O₅ in mol % 5.0 5.0 6.0 6.0 7.0 7.0 5.0 Na₂O in mol % 16.016.0 16.0 16.0 16.0 16.0 15.0 MgO in mol % 3.0 0.0 2.0 0.0 1.0 0.0 3.0ZnO in mol % 0.0 3.0 0.0 2.0 0.0 1.0 0.0 SnO₂ in mol % 0.0 0.0 0.0 0.00.0 0.0 0.0 CaO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O inmol % 0.84 0.84 0.89 0.89 0.94 0.94 0.83 (P₂O₅ + R₂O)/(M₂O₃) 1.31 1.311.38 1.38 1.44 1.44 1.33 in mol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.50 1.50 1.501.50 1.50 1.50 1.53 in mol % SiO₂ in wt % 51.1 50.2 50.3 49.8 49.6 49.453.1 Al₂O₃ in wt % 23.1 22.7 22.8 22.5 22.5 22.3 21.8 P₂O₅ in wt % 10.19.9 11.9 11.8 13.7 13.6 10.1 Na₂O in wt % 14.0 13.8 13.8 13.7 13.7 13.613.3 MgO in wt % 1.7 0.0 1.1 0.0 0.6 0.0 1.7 ZnO in wt % 0.0 3.4 0.0 2.20.0 1.1 0.0 SnO₂ in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CaO in wt % 0.0 0.00.0 0.0 0.0 0.0 0.0 Compositional none none none none none none noneanalysis Density (g/cm³) 2.417 2.453 2.406 2.428 2.393 2.404 2.423 MolarVolume 29.21 29.28 29.76 29.83 30.35 30.38 28.95 (cm³/mol) Strain Pt. (°C.) 643 621 623 619 611 621 680 Anneal Pt. (° C.) 696 681 684 681 675683 730 Softening Pt. (° C.) 964 954.3 963.5 963.4 965 967.4 989.1Temperature at 200 P 1668 1677 1695 1698 1714 1713 1676 Viscosity (° C.)Temperature at 35 kP 1247 1252 1268 1265 1280 1277 1252 Viscosity (° C.)Temperature at 160 1162 1166 1181 1178 1193 1190 1167 kP Viscosity (°C.) Liquidus 960 1100 Temperature (° C.) Liquidus Viscosity 1.85E+07 6.28E+05  (P) Zircon Breakdown 1240 >1265 Temperature (° C.) ZirconBreakdown 39255 <28281 Viscosity (P) Stress Optical 3.015 3.132 3.0553.122 2.999 Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 798 754767 745 778 778 824 temperature (° C.) 410° C. 1 hr 932 963 833 895 817820 970 Compressive Stress (MPa) 410° C. 1 hr Depth of 32 28 33 32 39 3933 Layer (mm) 410° C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2hr 901 959 813 874 797 796 959 Compressive Stress (MPa) 410° C. 2 hrDepth of 44 38 48 46 54 53 44 Layer (mm) 410° C. 2 hrVickers >30 >20 >20 >20 >20 >20 >20 Crack Initiation Load (kgf) 410° C.3 hr 895 949 808 868 787 781 Compressive Stress (MPa) 410° C. 3 hr Depthof 54 46 57 55 65 65 Layer (mm) 410° C. 4 hr 884 942 792 842 770 772Compressive Stress (MPa) 410° C. 4 hr Depth of 63 54 64 63 76 76 Layer(mm) 410° C. 4 hr Vickers Crack Initiation Load (kgf) 410° C. 8 hrCompressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL3.6E−10 2.8E−10 3.9E−10 3.6E−10 5.4E−10 5.4E−10 3.9E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 3.4E−10 2.6E−104.1E−10 3.7E−10 5.2E−10 5.0E−10 3.4E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 2 hr D FSM DOL 3.4E−10 2.5E−10 3.8E−10 3.6E−105.0E−10 5.0E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3 hrD FSM DOL 3.5E−10 2.6E−10 3.6E−10 3.5E−10 5.1E−10 5.1E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 8 hr Example Number 15 16 17 1819 20 21 SiO₂ in mol % 61.0 63.1 61.2 61.3 60.8 60.9 60.3 Al₂O₃ in mol %14.8 13.9 15.9 15.8 16.0 15.8 15.7 P₂O₅ in mol % 4.9 5.0 5.0 4.9 4.9 4.95.5 Na₂O in mol % 15.3 13.9 15.8 16.0 16.1 15.8 16.0 MgO in mol % 3.84.1 2.0 2.0 2.0 2.5 2.5 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ inmol % 0.0 0.0 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.0 0.1 0.0 0.0 0.0 0.00.0 (M₂O₃)/R_(x)O in mol % 0.77 0.77 0.90 0.88 0.88 0.86 0.85 (P₂O₅ +R₂O)/(M₂O₃) 1.36 1.36 1.30 1.32 1.31 1.31 1.37 in mol % (P₂O₅ +R_(x)O)/(M₂O₃) 1.63 1.65 1.43 1.45 1.44 1.47 1.53 in mol % SiO₂ in wt %52.5 54.6 52.0 52.1 51.7 51.9 51.0 Al₂O₃ in wt % 21.6 20.4 23.0 22.723.1 22.8 22.5 P₂O₅ in wt % 10.0 10.2 10.0 9.8 9.8 9.8 10.9 Na₂O in wt %13.6 12.4 13.8 14.0 14.1 13.9 13.9 MgO in wt % 2.2 2.4 1.1 1.1 1.1 1.41.4 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.0 0.0 0.1 0.20.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Compositional XRFXRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.411 2.404 2.413 2.4152.417 2.418 2.416 Molar Volume 28.98 28.89 29.32 29.26 29.28 29.17 29.38(cm³/mol) Strain Pt. (° C.) 659 672 631 630 628 630 631 Anneal Pt. (°C.) 709 734 689 687 685 683 685 Softening Pt. (° C.) 980.3 999.4 977.9973.6 969.2 968.2 960.6 Temperature at 200 P 1695 1711 1704 1699 16981691 1687 Viscosity (° C.) Temperature at 35 kP 1260 1270 1285 1273 12741268 1263 Viscosity (° C.) Temperature at 160 1173 1183 1197 1187 11881182 1177 kP Viscosity (° C.) Liquidus 970 Temperature (° C.) LiquidusViscosity 2.97E+07 (P) Zircon Breakdown >1260 Temperature (° C.) ZirconBreakdown <52623 Viscosity (P) Stress Optical 3.095 3.014 Coefficient((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 797 831 787 784 781 775 782temperature (° C.) 410° C. 1 hr 919 875 918 966 954 Compressive Stress(MPa) 410° C. 1 hr Depth of 36 32 37 35 35 Layer (mm) 410° C. 1 hrVickers Crack Initiation Load (kgf) 410° C. 2 hr 917 863 879 906 926 942912 Compressive Stress (MPa) 410° C. 2 hr Depth of 48 45 47 49 46 48 47Layer (mm) 410° C. 2 hr Vickers >20 15-20 >20 15-20 15-20 15-20 15-20Crack Initiation Load (kgf) 410° C. 3 hr 881 855 856 906 924 910 878Compressive Stress (MPa) 410° C. 3 hr Depth of 56 56 57 59 55 56 55Layer (mm) 410° C. 4 hr 874 854 858 869 898 896 Compressive Stress (MPa)410° C. 4 hr Depth of 65 65 66 67 64 65 Layer (mm) 410° C. 4 hr VickersCrack Initiation Load (kgf) 410° C. 8 hr Compressive Stress (MPa) 410°C. 8 hr Depth of Layer (mm) D FSM DOL 4.6E−10 3.6E−10 4.9E−10 4.3E−104.3E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSMDOL 4.1E−10 3.6E−10 3.9E−10 4.3E−10 3.7E−10 4.1E−10 3.9E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL 3.7E−10 3.7E−103.8E−10 4.1E−10 3.6E−10 3.7E−10 3.6E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 3 hr D FSM DOL 3.7E−10 3.7E−10 4.0E−10 3.6E−103.7E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSMDOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8 hr ExampleNumber 22 23 24 25 26 27 28 SiO₂ in mol % 60.3 62.3 61.3 60.8 60.5 62.262.1 Al₂O₃ in mol % 15.9 14.7 15.7 16.0 15.9 14.6 14.6 P₂O₅ in mol % 5.54.9 5.0 5.0 5.2 5.0 5.0 Na₂O in mol % 16.2 15.0 16.0 16.1 16.3 15.1 15.2MgO in mol % 1.9 2.0 1.9 2.0 2.0 3.1 0.1 ZnO in mol % 0.0 0.0 0.0 0.00.0 0.0 3.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.01.0 0.0 0.0 0.0 0.1 0.0 (M₂O₃)/R_(x)O in mol % 0.88 0.82 0.87 0.88 0.870.80 0.80 (P₂O₅ + R₂O)/(M₂O₃) 1.36 1.36 1.34 1.32 1.35 1.37 1.38 in mol% (P₂O₅ + R_(x)O)/(M₂O₃) 1.48 1.56 1.46 1.45 1.47 1.59 1.59 in mol %SiO₂ in wt % 50.9 53.3 52.1 51.6 51.2 53.4 52.4 Al₂O₃ in wt % 22.8 21.322.6 23.0 22.9 21.2 20.9 P₂O₅ in wt % 10.9 10.0 10.0 10.0 10.4 10.1 9.9Na₂O in wt % 14.1 13.2 14.0 14.1 14.2 13.3 13.2 MgO in wt % 1.1 1.1 1.11.1 1.1 1.8 0.0 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 3.4 SnO₂ in wt % 0.20.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.8 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.4152.415 2.414 2.417 2.416 2.413 2.449 Molar Volume 29.49 29.07 29.30 29.3129.40 29.02 29.10 (cm³/mol) Strain Pt. (° C.) 632 644 638 639 636 652614 Anneal Pt. (° C.) 688 695 694 696 694 702 671 Softening Pt. (° C.)965.7 980.7 975.7 972.1 970.6 977.2 950 Temperature at 200 P 1690 16991703 1698 1691 1704 1702 Viscosity (° C.) Temperature at 35 kP 1267 12671278 1275 1269 1263 1253 Viscosity (° C.) Temperature at 160 1181 11791191 1189 1183 1178 1167 kP Viscosity (° C.) Liquidus Temperature (° C.)Liquidus Viscosity (P) Zircon Breakdown Temperature (° C.) ZirconBreakdown Viscosity (P) Stress Optical 3.058 3.045 3.029 3.045 3.0413.044 3.156 Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 773 795780 782 769 796 762 temperature (° C.) 410° C. 1 hr 873 901 CompressiveStress (MPa) 410° C. 1 hr Depth of 33 29 Layer (mm) 410° C. 1 hr VickersCrack Initiation Load (kgf) 410° C. 2 hr 900 858 902 906 909 870 862Compressive Stress (MPa) 410° C. 2 hr Depth of 47 47 47 47 46 47 41Layer (mm) 410° C. 2 hr Vickers >20 15-20 15-20 15-20 >20 >20 15-20Crack Initiation Load (kgf) 410° C. 3 hr 896 846 890 906 900 862 880Compressive Stress (MPa) 410° C. 3 hr Depth of 55 56 56 55 53 55 49Layer (mm) 410° C. 4 hr 864 870 Compressive Stress (MPa) 410° C. 4 hrDepth of 61 54 Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load(kgf) 410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer(mm) D FSM DOL 3.9E−10 3.0E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5at 410° C. 1 hr D FSM DOL 3.9E−10 3.9E−10 3.9E−10 3.9E−10 3.7E−103.9E−10 3.0E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 2 hrD FSM DOL 3.6E−10 3.7E−10 3.7E−10 3.6E−10 3.3E−10 3.6E−10 2.8E−10 ~1.4 *2 * (Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL 3.3E−102.6E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSMDOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8 hr ExampleNumber 29 30 31 32 33 34 35 SiO₂ in mol % 62.2 60.3 60.0 60.0 59.9 60.760.3 Al₂O₃ in mol % 14.8 15.6 15.6 15.8 15.7 15.4 15.5 P₂O₅ in mol % 5.05.0 5.0 5.0 5.0 4.9 5.4 Na₂O in mol % 15.3 15.9 16.2 16.4 16.3 15.9 15.8MgO in mol % 2.5 3.0 0.0 2.6 2.9 2.9 3.0 ZnO in mol % 0.0 0.0 3.1 0.00.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.00.1 0.0 0.0 0.1 0.1 0.1 (M₂O₃)/R_(x)O in mol % 0.83 0.82 0.81 0.83 0.820.82 0.82 (P₂O₅ + R₂O)/(M₂O₃) 1.37 1.34 1.36 1.35 1.35 1.35 1.37 in mol% (P₂O₅ + R_(x)O)/(M₂O₃) 1.54 1.54 1.56 1.52 1.54 1.54 1.56 in mol %SiO₂ in wt % 53.2 51.4 50.3 51.0 51.0 51.8 51.2 Al₂O₃ in wt % 21.5 22.522.1 22.8 22.7 22.4 22.3 P₂O₅ in wt % 10.0 10.1 9.8 10.0 10.1 10.0 10.8Na₂O in wt % 13.5 14.0 14.0 14.4 14.3 14.0 13.8 MgO in wt % 1.5 1.7 0.01.5 1.7 1.7 1.7 ZnO in wt % 0.0 0.0 3.5 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.20.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.4112.424 2.46 2.423 2.426 2.422 2.422 Molar Volume 29.12 29.07 29.15 29.1729.08 29.06 29.20 (cm³/mol) Strain Pt. (° C.) 642 646 618 641 633 630625 Anneal Pt. (° C.) 696 696 674 693 682 681 676 Softening Pt. (° C.)972.7 960.3 941.8 960 952.8 957.2 950.7 Temperature at 200 P 1713 16641668 1676 1670 1673 1672 Viscosity (° C.) Temperature at 35 kP 1271 12401238 1246 1243 1250 1241 Viscosity (° C.) Temperature at 160 1185 11551153 1162 1160 1164 1157 kP Viscosity (° C.) Liquidus 995 975Temperature (° C.) Liquidus Viscosity 6.97E+06  1.21E+07  (P) ZirconBreakdown 1240 1265 Temperature (° C.) Zircon Breakdown 41251 23823Viscosity (P) Stress Optical 3.05 2.938 3.112 3.009 2.994 3.018 3.266??Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 795 794 749 791 779775 772 temperature (° C.) 410° C. 1 hr 921 927 Compressive Stress (MPa)410° C. 1 hr Depth of 28 33 Layer (mm) 410° C. 1 hr Vickers CrackInitiation Load (kgf) 410° C. 2 hr 868 943 921 946 948 890 834Compressive Stress (MPa) 410° C. 2 hr Depth of 48 46 41 48 46 44 48Layer (mm) 410° C. 2 hr Vickers >20 >20 15-20 10-15 10-15 >20 >20 CrackInitiation Load (kgf) 410° C. 3 hr 862 941 895 921 936 885 818Compressive Stress (MPa) 410° C. 3 hr Depth of 55 54 47 55 51 55 52Layer (mm) 410° C. 4 hr 894 924 875 Compressive Stress (MPa) 410° C. 4hr Depth of 52 61 63 Layer (mm) 410° C. 4 hr Vickers Crack InitiationLoad (kgf) 410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth ofLayer (mm) D FSM DOL 2.8E−10 3.9E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 1 hr D FSM DOL 4.1E−10 3.7E−10 3.0E−10 4.1E−103.7E−10 3.4E−10 4.1E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 2 hr D FSM DOL 3.6E−10 3.4E−10 2.6E−10 3.6E−10 3.1E−10 3.6E−103.2E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSMDOL 2.4E−10 3.3E−10 3.5E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at410° C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 8 hr Example Number 36 37 38 39 40 41 42 SiO₂ in mol % 60.0 60.4 60.262.8 61.3 61.1 60.9 Al₂O₃ in mol % 15.6 15.6 15.5 14.4 15.1 15.2 15.3P₂O₅ in mol % 5.5 5.0 4.9 4.1 4.7 4.8 4.9 Na₂O in mol % 16.3 16.4 16.415.6 15.7 15.8 15.8 MgO in mol % 2.5 2.5 2.9 3.0 3.0 3.0 3.0 ZnO in mol% 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1CaO in mol % 0.0 0.0 0.1 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.830.83 0.80 0.77 0.81 0.81 0.81 (P₂O₅ + R₂O)/(M₂O₃) 1.39 1.37 1.38 1.371.35 1.35 1.35 in mol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.55 1.53 1.57 1.58 1.551.55 1.55 in mol % SiO₂ in wt % 50.8 51.4 51.4 54.5 52.6 52.3 52.1 Al₂O₃in wt % 22.4 22.5 22.4 21.1 22.0 22.1 22.2 P₂O₅ in wt % 10.9 10.1 9.98.3 9.5 9.7 9.9 Na₂O in wt % 14.2 14.4 14.4 14.0 13.9 13.9 13.9 MgO inwt % 1.4 1.4 1.7 1.7 1.7 1.7 1.7 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0SnO₂ in wt % 0.2 0.2 0.2 0.3 0.3 0.3 0.3 CaO in wt % 0.0 0.0 0.0 0.0 0.00.0 0.0 Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density(g/cm³) 2.419 2.421 2.427 2.422 2.422 2.422 2.422 Molar Volume 29.3529.17 29.00 28.58 28.92 28.98 29.03 (cm³/mol) Strain Pt. (° C.) 619 624632 653 635 634 632 Anneal Pt. (° C.) 672 677 680 704 685 684 682Softening Pt. (° C.) 954.2 956.8 952.6 977.4 963.1 961.8 957.4Temperature at 200 P 1675 1680 1659 1709 1693 1690 1689 Viscosity (° C.)Temperature at 35 kP 1246 1255 1229 1263 1257 1256 1254 Viscosity (° C.)Temperature at 160 1161 1169 1145 1176 1170 1170 1168 kP Viscosity (°C.) Liquidus 985 990 Temperature (° C.) Liquidus Viscosity 1.00E+079.03E+06  (P) Zircon Breakdown 1260 1240 Temperature (° C.) ZirconBreakdown 27805 45159 Viscosity (P) Stress Optical 2.986 3.005 3.008Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 767 768 778 793 773772 770 temperature (° C.) 410° C. 1 hr 925 979 973 967 967 CompressiveStress (MPa) 410° C. 1 hr Depth of 34 30 30 29 29 Layer (mm) 410° C. 1hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr 903 928 934 980 978975 948 Compressive Stress (MPa) 410° C. 2 hr Depth of 46 46 46 42 41 4141 Layer (mm) 410° C. 2 hr Vickers 15-20 10-15 15-20 15-20 15-20 15-2010-15 Crack Initiation Load (kgf) 410° C. 3 hr 923 943 930 934 927 925Compressive Stress (MPa) 410° C. 3 hr Depth of 54 53 53 51 51 51 Layer(mm) 410° C. 4 hr 920 949 948 943 941 Compressive Stress (MPa) 410° C. 4hr Depth of 59 59 57 57 57 Layer (mm) 410° C. 4 hr Vickers 15-20 15-2015-20 10-15 Crack Initiation Load (kgf) 410° C. 8 hr Compressive Stress(MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL 4.1E−10 3.2E−10 3.2E−103.0E−10 3.0E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 1 hrD FSM DOL  3.7E−10 3.7E−10 3.7E−10 3.1E−10 3.0E−10 3.0E−10 3.0E−10~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL3.4E−10 3.3E−10 3.3E−10 3.1E−10 3.1E−10 3.1E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL 3.1E−10 3.1E−102.9E−10 2.9E−10 2.9E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 4 hr Example Number 43 44 45 46 47 48 49 SiO₂ in mol % 60.4 60.2 60.160.0 59.9 60.1 59.3 Al₂O₃ in mol % 15.5 15.6 15.6 15.6 15.7 15.6 15.3P₂O₅ in mol % 5.0 5.0 5.1 5.1 5.1 5.2 5.7 Na₂O in mol % 15.9 16.0 16.016.0 16.1 16.1 16.5 MgO in mol % 3.0 3.0 3.0 3.0 3.0 2.9 2.9 ZnO in mol% 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1CaO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.820.82 0.82 0.82 0.82 0.82 0.79 (P₂O₅ + R₂O)/(M₂O₃) 1.35 1.35 1.35 1.351.35 1.37 1.46 in mol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.54 1.55 1.55 1.54 1.541.55 1.65 in mol % SiO₂ in wt % 51.5 51.3 51.2 51.1 51.0 51.2 50.2 Al₂O₃in wt % 22.4 22.5 22.6 22.6 22.7 22.5 22.0 P₂O₅ in wt % 10.1 10.2 10.210.2 10.3 10.4 11.4 Na₂O in wt % 14.0 14.0 14.0 14.1 14.1 14.1 14.5 MgOin wt % 1.7 1.7 1.7 1.7 1.7 1.6 1.7 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.00.0 SnO₂ in wt % 0.3 0.3 0.3 0.3 0.3 0.3 0.3 CaO in wt % 0.0 0.0 0.0 0.00.0 0.0 0.0 Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density(g/cm³) 2.423 2.424 2.425 2.424 2.424 2.423 2.424 Molar Volume 29.0929.10 29.10 29.11 29.14 29.14 29.27 (cm³/mol) Strain Pt. (° C.) 628 629633 630 629 615 603 Anneal Pt. (° C.) 680 680 680 681 680 664 651Softening Pt. (° C.) 954 952.8 956.5 953.3 953 944.5 929.6 Temperatureat 200 P 1684 1678 1676 1681 1678 1681 1665 Viscosity (° C.) Temperatureat 35 kP 1257 1245 1248 1249 1251 1242 1225 Viscosity (° C.) Temperatureat 160 1171 1160 1163 1166 1158 1141 kP Viscosity (° C.) LiquidusTemperature (° C.) Liquidus Viscosity (P) Zircon Breakdown Temperature(° C.) Zircon Breakdown Viscosity (P) Stress Optical Coefficient ((nm ·Mpa⁻¹ · mm⁻¹) Approximate Fictive 770 769 765 770 769 752 737temperature (° C.) 410° C. 1 hr 975 964 992 Compressive Stress (MPa)410° C. 1 hr Depth of 29 29 27 Layer (mm) 410° C. 1 hr Vickers CrackInitiation Load (kgf) 410° C. 2 hr 960 955 990 945 948 939 905Compressive Stress (MPa) 410° C. 2 hr Depth of 41 40 38 38 38 38 39Layer (mm) 410° C. 2 hr Vickers 25-30 25-30 >20 >20 >20 15-20 10-15Crack Initiation Load (kgf) 410° C. 3 hr 930 933 970 Compressive Stress(MPa) 410° C. 3 hr Depth of 50 50 53 Layer (mm) 410° C. 4 hr 948 940Compressive Stress (MPa) 410° C. 4 hr Depth of 56 56 Layer (mm) 410° C.4 hr Vickers 25-30 20-25 Crack Initiation Load (kgf) 410° C. 8 hrCompressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL3.0E−10 3.0E−10 2.6E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 1 hr D FSM DOL 3.0E−10 2.8E−10 2.6E−10 2.6E−10 2.6E−10 2.6E−102.7E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSMDOL 3.0E−10 3.0E−10 3.3E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at410° C. 3 hr D FSM DOL 2.8E−10 2.8E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 8 hr Example Number 50 51 52 53 54 55 56 SiO₂ in mol% 61.8 56.9 60.1 60.2 60.1 61.1 61.0 Al₂O₃ in mol % 13.5 13.4 15.0 15.415.2 14.6 14.9 P₂O₅ in mol % 5.0 10.0 6.0 5.4 5.7 5.4 5.5 Na₂O in mol %19.5 19.6 15.7 15.9 15.9 15.2 15.5 MgO in mol % 0.0 0.0 3.0 3.0 3.0 3.53.1 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.10.1 0.1 0.1 0.1 CaO in mol % 0.0 0.0 0.1 0.1 0.1 0.1 0.1 (M₂O₃)/R_(x)Oin mol % 0.69 0.68 0.80 0.81 0.80 0.78 0.80 (P₂O₅ + R₂O)/(M₂O₃) 1.822.21 1.44 1.38 1.42 1.41 1.41 in mol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.82 2.211.64 1.58 1.62 1.65 1.62 in mol % SiO₂ in wt % 52.9 46.0 50.9 51.2 50.952.2 51.9 Al₂O₃ in wt % 19.5 18.4 21.6 22.2 21.9 21.2 21.5 P₂O₅ in wt %10.1 19.1 11.9 10.7 11.3 10.9 11.0 Na₂O in wt % 17.2 16.3 13.7 13.9 13.913.4 13.6 MgO in wt % 0.0 0.0 1.7 1.7 1.7 2.0 1.7 ZnO in wt % 0.0 0.00.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.2 0.2 0.2 0.2 0.2 0.2 0.2 CaO in wt %0.0 0.0 0.0 0.0 0.0 0.0 0.0 Compositional XRF XRF XRF XRF XRF XRF XRFanalysis Density (g/cm³) 2.426 2.408 2.413 2.419 2.416 2.415 2.415 MolarVolume 28.96 30.85 29.45 29.23 29.34 29.10 29.21 (cm³/mol) Strain Pt. (°C.) 574 522 626 637 630 649 639 Anneal Pt. (° C.) 625 568 679 688 681701 689 Softening Pt. (° C.) 872.9 825.1 947.3 955.1 949.9 969.4 961Temperature at 200 P 1651 1587 1686 1679 1684 1678 1698 Viscosity (° C.)Temperature at 35 kP 1162 1126 1248 1253 1248 1248 1256 Viscosity (° C.)Temperature at 160 1075 1040 1162 1169 1163 1163 1172 kP Viscosity (°C.) Liquidus 990 915 1000 Temperature (° C.) Liquidus Viscosity 9.59E+052.61E+06 6.34E+06 (P) Zircon Breakdown 1235 >1245 1275 >1270 >1300Temperature (° C.) Zircon Breakdown 11856 <6194 22653 <26470 <15377Viscosity (P) Stress Optical 3.069 3.107 2.986 3.089 3.064 Coefficient((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 710 650 769 776 769 790 777temperature (° C.) 410° C. 1 hr 850 891 870 852 867 Compressive Stress(MPa) 410° C. 1 hr Depth of 47 37 38 37 38 Layer (mm) 410° C. 1 hrVickers Crack Initiation Load (kgf) 410° C. 2 hr 501 496 857 873 848 841829 Compressive Stress (MPa) 410° C. 2 hr Depth of 90 88 52 49 52 50 50Layer (mm) 410° C. 2 hr Vickers >20 >20 20-30 >20 >20 >20 10-15 CrackInitiation Load (kgf) 410° C. 3 hr 842 863 834 836 832 CompressiveStress (MPa) 410° C. 3 hr Depth of 59 64 63 63 64 Layer (mm) 410° C. 4hr 828 859 842 826 835 Compressive Stress (MPa) 410° C. 4 hr Depth of 7072 70 73 72 Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load (kgf)410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) DFSM DOL  7.8E−10 4.9E−10 5.1E−10 4.9E−10 5.1E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL  1.4E−09  1.4E−09 4.8E−10 4.3E−10 4.8E−10 4.4E−10 4.4E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 2 hr D FSM DOL  4.1E−10 4.8E−10 4.7E−10 4.7E−104.8E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSMDOL  4.3E−10 4.6E−10 4.3E−10 4.7E−10 4.6E−10 ~1.4 * 2 * (Dt){circumflexover ( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 8 hr Example Number 57 58 59 60 61 62 63 SiO₂ in mol% 60.2 60.2 60.3 60.4 60.3 60.4 60.2 Al₂O₃ in mol % 15.0 15.3 15.1 15.515.3 15.4 15.1 P₂O₅ in mol % 5.5 6.0 5.9 5.9 5.9 5.9 6.0 Na₂O in mol %15.6 15.4 15.1 15.4 15.3 15.4 15.2 MgO in mol % 3.5 3.0 3.6 2.5 3.1 2.83.4 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.10.1 0.1 0.1 0.1 CaO in mol % 0.1 0.0 0.1 0.0 0.1 0.1 0.1 (M₂O₃)/R_(x)Oin mol % 0.78 0.83 0.81 0.86 0.83 0.85 0.81 (P₂O₅ + R₂O)/(M₂O₃) 1.411.40 1.39 1.38 1.39 1.38 1.40 in mol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.65 1.591.63 1.54 1.59 1.56 1.63 in mol % SiO₂ in wt % 51.3 50.9 51.1 50.9 51.050.9 50.9 Al₂O₃ in wt % 21.7 21.9 21.7 22.2 21.9 22.1 21.7 P₂O₅ in wt %11.0 11.9 11.7 11.8 11.8 11.8 11.9 Na₂O in wt % 13.8 13.4 13.2 13.4 13.313.4 13.3 MgO in wt % 2.0 1.7 2.0 1.4 1.7 1.6 1.9 ZnO in wt % 0.0 0.00.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.2 0.2 0.2 0.2 0.2 0.2 0.2 CaO in wt %0.0 0.0 0.0 0.0 0.0 0.0 0.0 Compositional XRF XRF XRF XRF XRF XRF XRFanalysis Density (g/cm³) 2.42 2.41 2.42 2.41 2.42 2.41 2.41 Molar Volume29.13 29.49 29.32 29.57 29.43 29.50 29.41 (cm³/mol) Strain Pt. (° C.)647 627 634 624 627 625 627 Anneal Pt. (° C.) 697 682 684 680 680 679679 Softening Pt. (° C.) 962.8 952 959.1 954.6 951 951.6 954.9Temperature at 200 P 1677 1728 1679 1693 1685 1687 1673 Viscosity (° C.)Temperature at 35 kP 1247 1257 1246 1259 1253 1257 1235 Viscosity (° C.)Temperature at 160 1163 1173 1160 1173 1168 1171 1151 kP Viscosity (°C.) Liquidus 1090 Temperature (° C.) Liquidus Viscosity 6.79E+05 (P)Zircon Breakdown 1265 >1250 Temperature (° C.) Zircon Breakdown 25644<27583 Viscosity (P) Stress Optical 3.046 3.092 3.085 3.037 Coefficient((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 784 776 778 779 779 773 787temperature (° C.) 410° C. 1 hr 883 Compressive Stress (MPa) 410° C. 1hr Depth of 37 Layer (mm) 410° C. 1 hr Vickers Crack Initiation Load(kgf) 410° C. 2 hr 870 879 910 878 869 885 885 Compressive Stress (MPa)410° C. 2 hr Depth of 52 46 45 47 50 46 45 Layer (mm) 410° C. 2 hrVickers >20 30-40 30-40 30-40 20-30 20-30 30-40 Crack Initiation Load(kgf) 410° C. 3 hr 861 Compressive Stress (MPa) 410° C. 3 hr Depth of 63Layer (mm) 410° C. 4 hr 853 Compressive Stress (MPa) 410° C. 4 hr Depthof 71 Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load (kgf) 410°C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) D FSMDOL 4.9E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 1 hr DFSM DOL 4.8E−10 3.8E−10  3.6E−10 3.9E−10 4.4E−10 3.7E−10 3.6E−10 ~1.4 *2 * (Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL 4.7E−10~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL4.5E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSMDOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8 hr ExampleNumber 64 65 66 67 68 69 70 SiO₂ in mol % 59.9 60.0 60.1 60.1 60.2 60.257.1 Al₂O₃ in mol % 15.5 15.3 15.5 15.2 15.4 15.0 17.5 P₂O₅ in mol % 5.45.3 3.6 5.6 5.8 5.8 6.8 Na₂O in mol % 15.9 15.6 15.5 15.4 15.4 15.2 18.4MgO in mol % 3.1 3.6 3.1 3.6 3.0 3.6 0.1 ZnO in mol % 0.0 0.0 0.0 0.00.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.00.0 0.0 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.81 0.80 0.83 0.80 0.830.80 0.95 (P₂O₅ + R₂O)/(M₂O₃) 1.38 1.37 1.24 1.38 1.39 1.40 1.44 in mol% (P₂O₅ + R_(x)O)/(M₂O₃) 1.58 1.60 1.44 1.61 1.58 1.63 1.45 in mol %SiO₂ in wt % 50.9 51.2 53.1 51.1 50.9 51.2 46.8 Al₂O₃ in wt % 22.3 22.123.1 21.9 22.0 21.7 24.2 P₂O₅ in wt % 10.8 10.7 7.6 11.2 11.7 11.6 13.2Na₂O in wt % 14.0 13.7 14.1 13.5 13.5 13.3 15.5 MgO in wt % 1.8 2.1 1.82.0 1.7 2.0 0.0 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.20.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.4192.421 2.417 2.419 2.415 2.416 2.41 Molar Volume 29.23 29.12 28.17 29.2329.43 29.29 30.41 (cm³/mol) Strain Pt. (° C.) 637 640 631 638 629 634619 Anneal Pt. (° C.) 689 689 683 687 681 684 679 Softening Pt. (° C.)958 962.4 956.3 962.4 954.1 959.7 953.7 Temperature at 200 P 1680 16701675 1665 1681 1676 1680 Viscosity (° C.) Temperature at 35 kP 1253 12491245 1240 1253 1247 1246 Viscosity (° C.) Temperature at 160 1168 11651159 1155 1167 1162 1165 kP Viscosity (° C.) Liquidus 855 Temperature (°C.) Liquidus Viscosity 1.99E+09 (P) Zircon Breakdown 1225 Temperature (°C.) Zircon Breakdown 50768 Viscosity (P) Stress Optical 2.997Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 778 776 773 774 771772 776 temperature (° C.) 410° C. 1 hr 808 Compressive Stress (MPa)410° C. 1 hr Depth of 43 Layer (mm) 410° C. 1 hr Vickers >50 CrackInitiation Load (kgf) 410° C. 2 hr 929 925 914 914 898 900 CompressiveStress (MPa) 410° C. 2 hr Depth of 48 47 49 48 50 48 Layer (mm) 410° C.2 hr Vickers >20 >20 >20 >20 >20 >20 Crack Initiation Load (kgf) 410° C.3 hr Compressive Stress (MPa) 410° C. 3 hr Depth of Layer (mm) 410° C. 4hr Compressive Stress (MPa) 410° C. 4 hr Depth of Layer (mm) 410° C. 4hr Vickers Crack Initiation Load (kgf) 410° C. 8 hr Compressive Stress(MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL  6.6E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 4.1E−10 3.9E−104.3E−10 4.1E−10 4.4E−10 4.1E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5at 410° C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at410° C. 3 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8hr Example Number 71 72 73 74 75 76 77 SiO₂ in mol % 56.4 55.5 56.2 56.357.4 57.3 56.4 Al₂O₃ in mol % 17.4 17.4 16.5 14.5 16.6 14.5 16.5 P₂O₅ inmol % 8.0 8.9 8.0 7.9 7.0 6.9 7.9 Na₂O in mol % 18.1 18.0 18.1 18.0 17.818.1 19.0 MgO in mol % 0.1 0.1 1.0 3.1 1.0 3.0 0.0 ZnO in mol % 0.0 0.00.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol% 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.96 0.97 0.86 0.690.88 0.69 0.87 (P₂O₅ + R₂O)/(M₂O₃) 1.50 1.54 1.59 1.79 1.50 1.72 1.62 inmol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.50 1.55 1.65 2.00 1.56 1.93 1.62 in mol %SiO₂ in wt % 45.6 44.4 45.8 46.7 47.3 48.0 45.9 Al₂O₃ in wt % 23.9 23.722.8 20.4 23.2 20.6 22.8 P₂O₅ in wt % 15.2 16.8 15.4 15.5 13.6 13.8 15.1Na₂O in wt % 15.1 14.9 15.2 15.4 15.2 15.6 16.0 MgO in wt % 0.0 0.0 0.61.7 0.5 1.7 0.0 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.20.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.412.41 2.42 2.43 2.42 2.43 2.42 Molar Volume 30.82 31.19 30.54 29.86 30.1629.49 30.58 (cm³/mol) Strain Pt. (° C.) 603 591 586 571 601 588 586Anneal Pt. (° C.) 661 648 642 619 658 634 642 Softening Pt. (° C.) 932.5916.5 909.5 877.4 928.3 900.7 906.5 Temperature at 200 P 1653 1660 16411603 1660 1616 1644 Viscosity (° C.) Temperature at 35 kP 1227 1224 12141171 1233 1183 1212 Viscosity (° C.) Temperature at 160 1142 1138 11281086 1148 1098 1126 kP Viscosity (° C.) Liquidus 800 Temperature (° C.)Liquidus Viscosity 2.74E+09 (P) Zircon Breakdown 1265 Temperature (° C.)Zircon Breakdown 18914 Viscosity (P) Stress Optical 3.038 3.005 2.9982.992 2.977 Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 756 742735 703 752 717 734 temperature (° C.) 410° C. 1 hr 888 734 816 809Compressive Stress (MPa) 410° C. 1 hr Depth of 43 44 49 45 Layer (mm)410° C. 1 hr Vickers 40-50 Crack Initiation Load (kgf) 410° C. 2 hr 731706 706 804 775 711 Compressive Stress (MPa) 410° C. 2 hr Depth of 62 6260 58 59 68 Layer (mm) 410° C. 2 hr Vickers >40 >40 >20 30-40 >20 >20Crack Initiation Load (kgf) 410° C. 3 hr Compressive Stress (MPa) 410°C. 3 hr Depth of Layer (mm) 410° C. 4 hr Compressive Stress (MPa) 410°C. 4 hr Depth of Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load(kgf) 410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer(mm) D FSM DOL  6.6E−10 6.9E−10 8.5E−10 7.2E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 6.9E−10 6.8E−106.4E−10 5.9E−10 6.2E−10 8.3E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5at 410° C. 2 hr ~D FSM DOL 1.4 * 2 * (Dt){circumflex over ( )}0.5 at410° C. 3 hr ~D FSM DOL 1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8hr Example Number 78 79 80 81 82 83 84 SiO₂ in mol % 56.3 57.2 57.6 50.456.4 55.9 55.4 Al₂O₃ in mol % 15.5 16.5 15.5 19.8 18.1 18.1 18.1 P₂O₅ inmol % 7.9 6.9 6.8 9.8 7.2 7.7 7.7 Na₂O in mol % 20.0 19.1 20.0 19.9 18.218.2 18.1 MgO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.6 ZnO in mol % 0.0 0.00.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol% 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.78 0.86 0.78 0.990.99 0.99 0.96 (P₂O₅ + R₂O)/(M₂O₃) 1.80 1.58 1.73 1.50 1.41 1.43 1.43 inmol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.80 1.58 1.73 1.50 1.41 1.43 1.46 in mol %SiO₂ in wt % 46.1 47.0 47.7 39.4 45.8 45.2 44.9 Al₂O₃ in wt % 21.5 23.021.7 26.3 24.9 24.8 24.8 P₂O₅ in wt % 15.3 13.5 13.3 18.1 13.9 14.7 14.7Na₂O in wt % 16.9 16.2 17.0 16.0 15.2 15.1 15.1 MgO in wt % 0.0 0.0 0.00.0 0.0 0.0 0.3 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.20.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.422.42 2.43 2.42 2.41 2.41 2.42 Molar Volume 30.36 30.22 29.94 31.72 30.6530.81 30.74 (cm³/mol) Strain Pt. (° C.) 572 601 582 588 617 610 607Anneal Pt. (° C.) 624 658 634 644 676 670 664 Softening Pt. (° C.) 879.4924.2 888.5 904 951.4 947.1 939.1 Temperature at 200 P 1623 1659 16341603 1672 1660 1664 Viscosity (° C.) Temperature at 35 kP 1180 1224 11901192 1254 1250 1233 Viscosity (° C.) Temperature at 160 1093 1138 11041111 1170 1166 1152 kP Viscosity (° C.) Liquidus 865 800 Temperature (°C.) Liquidus Viscosity 5.74E+08 5.51E+09 (P) Zircon Breakdown 1215 1245Temperature (° C.) Zircon Breakdown 69204 38105 Viscosity (P) StressOptical 2.97 2.935 2.999 3.051 3.028 3.044 Coefficient ((nm · Mpa⁻¹ ·mm⁻¹) Approximate Fictive 692 751 699 716 750 750 740 temperature (° C.)410° C. 1 hr 694 750 796 909 887 843 Compressive Stress (MPa) 410° C. 1hr Depth of 64 60 46 41 42 41 Layer (mm) 410° C. 1 hr Vickers30-40 >50 >50 Crack Initiation Load (kgf) 410° C. 2 hr 680 751 732 749837 Compressive Stress (MPa) 410° C. 2 hr Depth of 81 66 75 63 56 Layer(mm) 410° C. 2 hr Vickers >20 >20 >30 30-40 >40 Crack Initiation Load(kgf) 410° C. 3 hr Compressive Stress (MPa) 410° C. 3 hr Depth of Layer(mm) 410° C. 4 hr Compressive Stress (MPa) 410° C. 4 hr Depth of Layer(mm) 410° C. 4 hr Vickers Crack Initiation Load (kgf) 410° C. 8 hrCompressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL1.5E−09 1.3E−09 7.5E−10  6.0E−10  6.3E−10 6.0E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 1.2E−09 7.8E−101.0E−09 7.0E−10 5.6E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 4 hr DFSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8 hr ExampleNumber 85 86 87 88 89 90 91 SiO₂ in mol % 58.3 58.3 58.6 58.3 58.4 58.459.2 Al₂O₃ in mol % 15.8 15.6 15.4 15.6 15.4 15.1 15.3 P₂O₅ in mol % 6.86.7 6.7 6.8 6.7 6.7 6.8 Na₂O in mol % 15.9 15.7 15.2 15.6 15.4 15.1 15.5MgO in mol % 3.1 3.0 3.1 3.5 3.5 3.5 3.1 ZnO in mol % 0.0 0.5 0.9 0.00.5 1.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.10.1 0.1 0.1 0.1 0.1 0.1 (M₂O₃)/R_(x)O in mol % 0.83 0.81 0.80 0.81 0.790.77 0.82 (P₂O₅ + R₂O)/(M₂O₃) 1.43 1.43 1.42 1.44 1.44 1.45 1.45 in mol% (P₂O₅ + R_(x)O)/(M₂O₃) 1.63 1.66 1.68 1.67 1.70 1.75 1.66 in mol %SiO₂ in wt % 48.6 48.6 48.9 48.8 48.8 48.9 49.5 Al₂O₃ in wt % 22.4 22.121.9 22.1 21.8 21.5 21.7 P₂O₅ in wt % 13.4 13.2 13.1 13.4 13.3 13.3 13.4Na₂O in wt % 13.6 13.5 13.1 13.5 13.3 13.1 13.4 MgO in wt % 1.7 1.7 1.72.0 2.0 2.0 1.7 ZnO in wt % 0.0 0.5 1.0 0.0 0.5 1.1 0.0 SnO₂ in wt % 0.20.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.422.42 2.43 2.42 2.42 2.43 2.41 Molar Volume 29.81 29.70 29.62 29.72 29.6329.52 29.78 (cm³/mol) Strain Pt. (° C.) 612 614 611 615 614 616 612Anneal Pt. (° C.) 664 666 661 666 663 664 666 Softening Pt. (° C.) 932.6935.5 928.4 934 932.5 932.8 942.5 Temperature at 200 P 1660 1656 16541655 1651 1650 1675 Viscosity (° C.) Temperature at 35 kP 1235 1231 12261232 1227 1220 1244 Viscosity (° C.) Temperature at 160 1150 1147 11411147 1143 1136 1158 kP Viscosity (° C.) Liquidus 975 Temperature (° C.)Liquidus Viscosity 1.07E+07  (P) Zircon Breakdown >1300 Temperature (°C.) Zircon Breakdown <14599 Viscosity (P) Stress Optical 3.109 3.1123.069 3.049 3.082 3.021 3.03 Coefficient ((nm · Mpa⁻¹ · mm⁻¹)Approximate Fictive 753 755 748 754 749 749 758 temperature (° C.) 410°C. 1 hr 873 Compressive Stress (MPa) 410° C. 1 hr Depth of 33 Layer (mm)410° C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr 861 862861 850 881 874 853 Compressive Stress (MPa) 410° C. 2 hr Depth of 49 4746 47 46 45 45 Layer (mm) 410° C. 2 hrVickers >40 >40 >40 >40 >40 >40 >50 Crack Initiation Load (kgf) 410° C.3 hr Compressive Stress (MPa) 410° C. 3 hr Depth of Layer (mm) 410° C. 4hr Compressive Stress (MPa) 410° C. 4 hr Depth of Layer (mm) 410° C. 4hr Vickers Crack Initiation Load (kgf) 410° C. 8 hr Compressive Stress(MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL 3.9E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 4.3E−10 3.9E−103.7E−10 3.9E−10 3.7E−10 3.6E−10 3.6E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 3 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 8 hr Example Number 92 93 94 95 96 97 98 SiO₂ in mol% 59.2 59.3 59.3 59.3 59.2 59.3 58.4 Al₂O₃ in mol % 15.0 14.8 15.1 14.814.6 15.1 16.0 P₂O₅ in mol % 6.8 6.8 6.8 6.8 6.8 6.7 6.8 Na₂O in mol %15.2 14.9 15.1 14.9 14.8 15.2 15.9 MgO in mol % 3.1 3.0 3.5 3.6 3.6 3.62.7 ZnO in mol % 0.5 1.0 0.0 0.5 1.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.10.1 0.1 0.1 0.1 CaO in mol % 0.1 0.1 0.1 0.1 0.1 0.0 0.0 (M₂O₃)/R_(x)Oin mol % 0.80 0.78 0.81 0.78 0.75 0.80 0.86 (P₂O₅ + R₂O)/(M₂O₃) 1.461.47 1.45 1.46 1.48 1.45 1.41 in mol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.71 1.741.69 1.74 1.80 1.69 1.58 in mol % SiO₂ in wt % 49.6 49.6 49.7 49.8 49.749.9 48.7 Al₂O₃ in wt % 21.3 21.0 21.5 21.1 20.7 21.5 22.7 P₂O₅ in wt %13.4 13.4 13.5 13.4 13.4 13.3 13.3 Na₂O in wt % 13.2 12.9 13.1 12.9 12.813.2 13.7 MgO in wt % 1.7 1.7 2.0 2.0 2.0 2.0 1.5 ZnO in wt % 0.6 1.10.0 0.6 1.1 0.0 0.0 SnO₂ in wt % 0.2 0.2 0.2 0.2 0.2 0.1 0.1 CaO in wt %0.0 0.0 0.0 0.0 0.0 0.0 0.0 Compositional XRF XRF XRF XRF XRF XRF XRFanalysis Density (g/cm³) 2.43 2.41 2.41 2.42 2.43 2.411 2.414 MolarVolume 29.61 29.79 29.71 29.59 29.48 29.64 29.87 (cm³/mol) Strain Pt. (°C.) 615 613 617 620 620 616 612 Anneal Pt. (° C.) 669 663 668 671 669669 666 Softening Pt. (° C.) 936.3 934.5 939.7 938.2 942.5 940.7 940.2Temperature at 200 P 1667 1666 1663 1670 1657 1666 1661 Viscosity (° C.)Temperature at 35 kP 1241 1234 1233 1235 1216 1240 1243 Viscosity (° C.)Temperature at 160 1156 1148 1147 1151 1133 1153 1158 kP Viscosity (°C.) Liquidus Temperature (° C.) Liquidus Viscosity (P) Zircon BreakdownTemperature (° C.) Zircon Breakdown Viscosity (P) Stress Optical 3.0673.117 3.08 3.115 3.091 Coefficient ((nm · Mpa⁻¹ · mm⁻¹) ApproximateFictive 760 751 757 759 756 760 758 temperature (° C.) 410° C. 1 hr 864896 Compressive Stress (MPa) 410° C. 1 hr Depth of 29 30 Layer (mm) 410°C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr 831 844 832 850838 870 889 Compressive Stress (MPa) 410° C. 2 hr Depth of 46 44 45 4744 43 42 Layer (mm) 410° C. 2 hr Vickers >40 >40 >40 >40 >40 40-50 >50Crack Initiation Load (kgf) 410° C. 3 hr Compressive Stress (MPa) 410°C. 3 hr Depth of Layer (mm) 410° C. 4 hr Compressive Stress (MPa) 410°C. 4 hr Depth of Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load(kgf) 410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer(mm) D FSM DOL 3.0E−10 3.2E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5at 410° C. 1 hr D FSM DOL 3.7E−10 3.4E−10 3.6E−10 3.9E−10 3.4E−103.3E−10 3.1E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 2 hrD FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSMDOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSM DOL~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8 hr Example Number99 100 101 102 103 104 105 SiO₂ in mol % 58.2 59.4 56.6 56.3 59.9 60.560.9 Al₂O₃ in mol % 15.6 16.0 16.0 16.1 15.1 15.1 15.0 P₂O₅ in mol % 6.86.8 7.6 7.7 6.8 6.8 6.8 Na₂O in mol % 15.8 16.0 15.9 16.2 15.1 15.0 15.1MgO in mol % 3.6 1.7 3.7 3.6 3.1 2.6 2.1 ZnO in mol % 0.0 0.0 0.0 0.00.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.00.0 0.0 0.0 0.0 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.80 0.90 0.82 0.81 0.830.86 0.88 (P₂O₅ + R₂O)/(M₂O₃) 1.45 1.43 1.47 1.48 1.45 1.44 1.46 in mol% (P₂O₅ + R_(x)O)/(M₂O₃) 1.68 1.53 1.70 1.71 1.66 1.61 1.59 in mol %SiO₂ in wt % 48.7 49.3 46.8 46.5 50.2 50.7 50.9 Al₂O₃ in wt % 22.1 22.622.5 22.6 21.4 21.4 21.3 P₂O₅ in wt % 13.4 13.3 14.9 15.0 13.5 13.4 13.5Na₂O in wt % 13.6 13.8 13.6 13.8 13.0 13.0 13.0 MgO in wt % 2.0 1.0 2.12.0 1.7 1.4 1.2 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.10.1 0.1 0.1 0.1 0.1 0.1 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.4152.406 2.417 2.417 2.405 2.4 2.396 Molar Volume 29.70 30.05 30.04 30.0829.78 29.87 29.98 (cm³/mol) Strain Pt. (° C.) 612 613 596 598 607 607613 Anneal Pt. (° C.) 664 671 649 652 663 663 671 Softening Pt. (° C.)937.7 951.1 918.5 919.9 945.2 949.4 955.8 Temperature at 200 P 1658 16981631 1637 1682 1695 1709 Viscosity (° C.) Temperature at 35 kP 1235 12621215 1219 1251 1262 1271 Viscosity (° C.) Temperature at 160 1150 11761131 1135 1164 1174 1182 kP Viscosity (° C.) Liquidus Temperature (° C.)Liquidus Viscosity (P) Zircon Breakdown Temperature (° C.) ZirconBreakdown Viscosity (P) Stress Optical Coefficient ((nm · Mpa⁻¹ · mm⁻¹)Approximate Fictive 754 767 739 743 758 759 768 temperature (° C.) 410°C. 1 hr 895 889 855 853 839 823 817 Compressive Stress (MPa) 410° C. 1hr Depth of 29 32 28 28 30 31 31 Layer (mm) 410° C. 1 hr Vickers CrackInitiation Load (kgf) 410° C. 2 hr 890 843 865 856 846 820 803Compressive Stress (MPa) 410° C. 2 hr Depth of 43 49 41 42 44 45 46Layer (mm) 410° C. 2 hr Vickers >50 >50 >50 >50 40-50 40-50 40-50 CrackInitiation Load (kgf) 410° C. 3 hr Compressive Stress (MPa) 410° C. 3 hrDepth of Layer (mm) 410° C. 4 hr Compressive Stress (MPa) 410° C. 4 hrDepth of Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load (kgf)410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) DFSM DOL 3.0E−10 3.6E−10 2.8E−10 2.8E−10 3.2E−10 3.4E−10 3.4E−10 ~1.4 *2 * (Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 3.3E−104.3E−10 3.0E−10 3.1E−10 3.4E−10 3.6E−10 3.7E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 8 hr Example Number 106 107 108109 110 111 112 113 SiO₂ in mol % 56.8 55.8 55.7 55.9 56.0 55.8 55.859.9 Al₂O₃ in mol % 17.9 18.0 18.0 18.0 18.0 18.0 18.0 15.7 P₂O₅ in mol% 7.2 7.8 7.8 7.7 7.7 7.7 7.8 5.4 Na₂O in mol % 17.9 16.1 16.3 16.6 16.617.0 17.0 16.2 MgO in mol % 0.1 2.0 0.1 1.5 0.1 1.3 0.1 2.6 ZnO in mol %0.0 0.0 2.0 0.0 1.4 0.0 1.2 0.0 SnO₂ in mol % 0.0 0.1 0.1 0.1 0.1 0.10.1 0.1 CaO in mol % 0.0 0.1 0.0 0.1 0.0 0.0 0.0 0.1 (M₂O₃)/R_(x)O in0.99 0.99 0.98 0.99 1.00 0.99 0.98 0.83 mol % (P₂O₅ + 1.40 1.33 1.341.35 1.35 1.37 1.38 1.38 R₂O)/(M₂O₃) in mol % (P₂O₅ + 1.41 1.44 1.451.44 1.43 1.44 1.45 1.55 R_(x)O)/(M₂O₃) in mol % SiO₂ in wt % 46.3 45.344.8 45.3 45.1 45.3 44.9 50.7 Al₂O₃ in wt % 24.7 24.9 24.6 24.8 24.624.8 24.6 22.5 P₂O₅ in wt % 13.9 14.9 14.7 14.8 14.6 14.8 14.8 10.9 Na₂Oin wt % 15.0 13.5 13.5 13.9 13.8 14.2 14.1 14.2 MgO in wt % 0.0 1.1 0.00.8 0.0 0.7 0.0 1.5 ZnO in wt % 0.0 0.0 2.1 0.0 1.6 0.0 1.4 0.0 SnO₂ inwt % 0.0 0.2 0.2 0.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.00.0 0.0 Compositional XRF XRF XRF XRF XRF XRF XRF XRF analysis Density2.409 2.411 2.436 2.411 2.430 2.411 2.427 2.419 (g/cm³) Molar Volume30.63 30.69 30.69 30.71 30.70 30.72 30.74 29.34 (cm³/mol) Strain Pt. (°C.) 617 621 609 618 604 617 613 629 Anneal Pt. 677 679 666 676 663 676671 684 (° C.) Softening Pt. 956.5 950.7 935.8 949.4 939 949.5 941.5 953(° C.) Temperature at 1673 1651 1650 1655 1659 1661 1681 1681 200 PViscosity (° C.) Temperature at 1259 1247 1238 1247 1242 1250 1256 125635 kP Viscosity (° C.) Temperature at 1174 1164 1154 1164 1161 1167 11711171 160 kP Viscosity (° C.) Liquidus Temperature (° C.) LiquidusViscosity (P) Zircon Breakdown Temperature (° C.) Zircon BreakdownViscosity (P) Stress Optical 3.088 3.118 3.127 3.183 3.036 3.124 3.147Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate 775 751 742 755 736 751 745775 Fictive temperature (° C.) 410° C. 1 hr 869 916 912 921 899 922 969Compressive Stress (MPa) 410° C. 1 hr 29 29 32 32 33 32 30 Depth ofLayer (mm) 410° C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr854 884 895 892 901 868 889 933 Compressive Stress (MPa) 410° C. 2 hr 5942 44 46 46 49 49 46 Depth of Layer (mm) 410° C. 2hr >50 >50 >50 >50 >50 >50 >50 20-30 Vickers Crack Initiation Load (kgf)410° C. 3 hr Compressive Stress (MPa) 410° C. 3 hr Depth of Layer (mm)410° C. 4 hr Compressive Stress (MPa) 410° C. 4 hr Depth of Layer (mm)410° C. 4 hr Vickers Crack Initiation Load (kgf) 410° C. 8 hrCompressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL3.0E−10 3.0E−10 3.6E−10 3.6E−10 3.9E−10 3.6E−10 3.2E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 6.2E−10 3.1E−103.4E−10 3.7E−10 3.7E−10 4.3E−10 4.3E−10 3.7E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 8 hr Example Number 114 115 116117 118 119 120 SiO₂ in mol % 59.2 58.4 57.9 57.1 56.5 56.8 57.4 Al₂O₃in mol % 16.1 16.5 16.8 17.2 17.6 16.8 16.6 P₂O₅ in mol % 5.8 6.2 6.56.9 7.3 7.1 7.1 Na₂O in mol % 16.6 17.0 17.3 17.7 18.0 17.1 16.7 MgO inmol % 2.2 1.7 1.3 0.9 0.5 2.1 2.1 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.00.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.1 0.0 0.00.0 0.0 0.0 0.1 (M₂O₃)/R_(x)O in mol % 0.86 0.88 0.90 0.93 0.95 0.880.88 (P₂O₅ + R₂O)/(M₂O₃) 1.39 1.40 1.42 1.43 1.44 1.44 1.43 in mol %(P₂O₅ + R_(x)O)/(M₂O₃) 1.53 1.51 1.49 1.48 1.47 1.56 1.56 in mol % SiO₂in wt % 49.7 48.7 47.9 46.9 46.0 46.8 47.4 Al₂O₃ in wt % 22.9 23.3 23.624.0 24.4 23.5 23.3 P₂O₅ in wt % 11.5 12.2 12.8 13.5 14.0 13.8 13.8 Na₂Oin wt % 14.4 14.6 14.8 15.0 15.2 14.5 14.2 MgO in wt % 1.2 1.0 0.7 0.50.3 1.1 1.2 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.2 0.20.2 0.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.4182.415 2.416 2.416 2.414 2.419 2.415 Molar Volume 29.58 29.86 30.07 30.3030.54 30.14 30.14 (cm³/mol) Strain Pt. (° C.) 624 618 616 616 615 609610 Anneal Pt. (° C.) 681 677 675 674 674 666 666 Softening Pt. (° C.)954.9 950.5 948.1 947.9 949.3 930.8 940.6 Temperature at 200 P 1680 16731676 1670 1667 1654 1660 Viscosity (° C.) Temperature at 35 kP 1257 12531254 1250 1249 1235 1240 Viscosity (° C.) Temperature at 160 1171 11681169 1166 1164 1151 1156 kP Viscosity (° C.) Liquidus 955 Temperature (°C.) Liquidus Viscosity 2.67E+07 (P) Zircon Breakdown Temperature (° C.)Zircon Breakdown Viscosity (P) Stress Optical 3.038 3.050 3.080 3.0043.093 Coefficient ((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 764 750 745765 747 746 741 temperature (° C.) 410° C. 1 hr 942 953 918 899 888 921900 Compressive Stress (MPa) 410° C. 1 hr Depth of 30 31 34 36 38 34 34Layer (mm) 410° C. 1 hr Vickers >50 Crack Initiation Load (kgf) 410° C.2 hr 945 924 901 868 853 913 895 Compressive Stress (MPa) 410° C. 2 hrDepth of 46 47 50 54 50 46 45 Layer (mm) 410° C. 2 hr Vickers20-30 >50 >50 >40 >50 >50 30-40 Crack Initiation Load (kgf) 410° C. 3 hrCompressive Stress (MPa) 410° C. 3 hr Depth of Layer (mm) 410° C. 4 hrCompressive Stress (MPa) 410° C. 4 hr Depth of Layer (mm) 410° C. 4 hrVickers Crack Initiation Load (kgf) 410° C. 8 hr Compressive Stress(MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL 3.2E−10  3.4E−104.1E−10 4.6E−10 5.1E−10 4.1E−10 4.1E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 1 hr D FSM DOL 3.7E−10  3.9E−10 4.4E−10 5.2E−104.4E−10 3.7E−10 3.6E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 3hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 4 hr DFSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8 hr ExampleNumber 121 122 123 124 125 126 127 SiO₂ in mol % 57.9 57.0 57.4 58.059.0 58.9 58.9 Al₂O₃ in mol % 16.4 16.7 16.6 16.2 15.5 15.7 16.0 P₂O₅ inmol % 7.1 7.3 7.3 7.4 6.4 6.5 6.4 Na₂O in mol % 16.5 16.7 16.5 16.3 15.415.7 16.0 MgO in mol % 2.1 2.0 2.0 2.0 3.5 3.0 2.5 ZnO in mol % 0.0 0.00.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaO in mol% 0.1 0.1 0.0 0.1 0.1 0.1 0.1 (M₂O₃)/R_(x)O in mol % 0.88 0.89 0.89 0.880.82 0.84 0.86 (P₂O₅ + R₂O)/(M₂O₃) 1.44 1.43 1.44 1.46 1.41 1.41 1.40 inmol % (P₂O₅ + R_(x)O)/(M₂O₃) 1.56 1.56 1.57 1.59 1.64 1.60 1.56 in mol %SiO₂ in wt % 47.8 46.9 47.2 47.8 49.6 49.4 49.2 Al₂O₃ in wt % 23.0 23.423.1 22.6 22.1 22.4 22.7 P₂O₅ in wt % 13.8 14.2 14.3 14.4 12.8 12.8 12.7Na₂O in wt % 14.0 14.2 14.0 13.8 13.4 13.6 13.8 MgO in wt % 1.1 1.1 1.11.1 2.0 1.7 1.4 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.20.2 0.2 0.2 0.1 0.1 0.1 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0Compositional XRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.4112.415 2.412 2.409 2.415 2.414 2.413 Molar Volume 30.16 30.26 30.27 30.2629.59 29.70 29.79 (cm³/mol) Strain Pt. (° C.) 609 607 607 605 617 612613 Anneal Pt. (° C.) 667 663 663 662 669 666 669 Softening Pt. (° C.)941.6 937.7 936.6 940.1 940.6 941.4 948.7 Temperature at 200 P 1670 16581661 1665 1666 1669 1677 Viscosity (° C.) Temperature at 35 kP 1247 12381241 1244 1241 1244 1250 Viscosity (° C.) Temperature at 160 1161 11541156 1159 1156 1159 1165 kP Viscosity (° C.) Liquidus Temperature (° C.)Liquidus Viscosity (P) Zircon Breakdown Temperature (° C.) ZirconBreakdown Viscosity (P) Stress Optical 3.056 3.038 3.055 Coefficient((nm · Mpa⁻¹ · mm⁻¹) Approximate Fictive 742 742 739 730 765 755 754temperature (° C.) 410° C. 1 hr 885 889 876 857 Compressive Stress (MPa)410° C. 1 hr Depth of 34 35 34 35 Layer (mm) 410° C. 1 hr Vickers CrackInitiation Load (kgf) 410° C. 2 hr 874 870 861 838 907 889 896Compressive Stress (MPa) 410° C. 2 hr Depth of 46 47 47 47 43 44 45Layer (mm) 410° C. 2 hr Vickers >50 >50 >50 40-50 40-50 30-40 40-50Crack Initiation Load (kgf) 410° C. 3 hr Compressive Stress (MPa) 410°C. 3 hr Depth of Layer (mm) 410° C. 4 hr Compressive Stress (MPa) 410°C. 4 hr Depth of Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load(kgf) 410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer(mm) D FSM DOL 4.1E−10 4.3E−10 4.1E−10 4.3E−10 ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 3.7E−10 3.9E−103.9E−10 3.9E−10 3.3E−10 3.4E−10 3.6E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 3 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 8 hr Example Number 128 129 130 131 132 133 134 SiO₂in mol % 58.2 57.8 57.9 56.8 56.9 56.9 56.8 Al₂O₃ in mol % 16.1 16.516.3 16.5 16.8 17.0 17.5 P₂O₅ in mol % 6.3 6.5 6.4 6.5 6.4 6.4 6.4 Na₂Oin mol % 15.9 16.5 16.3 16.5 16.8 17.1 17.1 MgO in mol % 3.5 2.6 3.0 3.63.1 2.5 2.0 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.10.1 0.1 0.0 0.0 0.0 0.0 CaO in mol % 0.1 0.1 0.1 0.0 0.0 0.0 0.0(M₂O₃)/R_(x)O in mol % 0.83 0.86 0.84 0.82 0.84 0.86 0.91 (P₂O₅ +R₂O)/(M₂O₃) 1.38 1.39 1.39 1.40 1.38 1.38 1.34 in mol % (P₂O₅ +R_(x)O)/(M₂O₃) 1.60 1.55 1.58 1.62 1.56 1.53 1.46 in mol % SiO₂ in wt %48.8 48.2 48.3 47.5 47.4 47.3 47.0 Al₂O₃ in wt % 22.9 23.4 23.1 23.323.8 24.0 24.6 P₂O₅ in wt % 12.5 12.7 12.7 12.8 12.5 12.5 12.5 Na₂O inwt % 13.7 14.2 14.0 14.2 14.4 14.6 14.6 MgO in wt % 1.9 1.4 1.7 2.0 1.71.4 1.1 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.1 0.1 0.10.1 0.1 0.1 0.1 CaO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CompositionalXRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.421 2.419 2.4202.426 2.426 2.424 2.420 Molar Volume 29.58 29.82 29.72 29.64 29.70 29.8130.00 (cm³/mol) Strain Pt. (° C.) 615 616 616 615 615 623 624 Anneal Pt.(° C.) 666 671 670 666 669 679 681 Softening Pt. (° C.) 937.8 945.7941.6 930.6 933.9 949.7 952.4 Temperature at 200 P 1655 1658 1658 16411646 1646 1657 Viscosity (° C.) Temperature at 35 kP 1235 1236 1236 12241233 1236 1246 Viscosity (° C.) Temperature at 160 1152 1154 1154 11411151 1152 1162 kP Viscosity (° C.) Liquidus Temperature (° C.) LiquidusViscosity (P) Zircon Breakdown Temperature (° C.) Zircon BreakdownViscosity (P) Stress Optical 3.021 3.007 3.015 Coefficient ((nm · Mpa⁻¹· mm⁻¹) Approximate Fictive 763 743 764 760 760 748 748 temperature (°C.) 410° C. 1 hr Compressive Stress (MPa) 410° C. 1 hr Depth of Layer(mm) 410° C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr 925925 927 978 981 975 983 Compressive Stress (MPa) 410° C. 2 hr Depth of43 45 44 40 40 41 41 Layer (mm) 410° C. 2 hr Vickers 20-30 30-4020-30 >30 >30 >30 >30 Crack Initiation Load (kgf) 410° C. 3 hrCompressive Stress (MPa) 410° C. 3 hr Depth of Layer (mm) 410° C. 4 hrCompressive Stress (MPa) 410° C. 4 hr Depth of Layer (mm) 410° C. 4 hrVickers Crack Initiation Load (kgf) 410° C. 8 hr Compressive Stress(MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL 3.3E−10 3.6E−103.4E−10 2.8E−10 2.8E−10 3.0E−10 3.0E−10 ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 3 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over( )}0.5 at 410° C. 8 hr Example Number 135 136 137 138 139 140 141 SiO₂in mol % 57.8 58.8 55.8 55.9 55.8 57.8 56.9 Al₂O₃ in mol % 17.0 16.517.0 18.0 18.1 17.0 16.9 P₂O₅ in mol % 6.4 6.4 7.6 7.7 7.7 6.6 7.0 Na₂Oin mol % 16.6 16.2 17.3 16.2 16.7 17.2 17.0 MgO in mol % 2.0 2.0 0.1 0.10.1 0.1 0.1 ZnO in mol % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.10.1 0.1 0.1 0.1 0.1 0.1 CaO in mol % 0.0 0.0 2.0 2.0 1.5 1.2 2.0(M₂O₃)/R_(x)O in mol % 0.91 0.90 0.88 0.98 0.99 0.92 0.88 (P₂O₅ +R₂O)/(M₂O₃) 1.36 1.37 1.46 1.33 1.35 1.40 1.43 in mol % (P₂O₅ +R_(x)O)/(M₂O₃) 1.48 1.49 1.59 1.45 1.44 1.48 1.55 in mol % SiO₂ in wt %48.0 49.0 45.5 45.2 45.1 47.6 46.7 Al₂O₃ in wt % 23.9 23.3 23.5 24.724.8 23.8 23.5 P₂O₅ in wt % 12.6 12.6 14.7 14.8 14.8 12.8 13.6 Na₂O inwt % 14.2 13.9 14.5 13.5 13.9 14.6 14.4 MgO in wt % 1.1 1.1 0.1 0.1 0.00.0 0.1 ZnO in wt % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ in wt % 0.1 0.1 0.20.2 0.2 0.2 0.2 CaO in wt % 0.0 0.0 1.5 1.5 1.1 0.9 1.5 CompositionalXRF XRF XRF XRF XRF XRF XRF analysis Density (g/cm³) 2.416 2.410 2.4212.429 2.419 2.423 2.427 Molar Volume 29.96 29.93 30.46 30.56 30.71 30.0930.16 (cm³/mol) Strain Pt. (° C.) 619 620 623 607 620 622 615 Anneal Pt.(° C.) 676 677 680 660 676 679 669 Softening Pt. (° C.) 948.8 957.8947.1 916.9 944.6 946.4 928 Temperature at 200 P 1673 1684 1638 16521650 1674 1656 Viscosity (° C.) Temperature at 35 kP 1254 1261 1214 12381242 1248 1230 Viscosity (° C.) Temperature at 160 1171 1176 1130 11561157 1163 1147 kP Viscosity (° C.) Liquidus Temperature (° C.) LiquidusViscosity (P) Zircon Breakdown Temperature (° C.) Zircon BreakdownViscosity (P) Stress Optical Coefficient ((nm · Mpa⁻¹ · mm⁻¹)Approximate Fictive 754 755 730 753 750 749 753 temperature (° C.) 410°C. 1 hr Compressive Stress (MPa) 410° C. 1 hr Depth of Layer (mm) 410°C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr 953 922 895 898896 925 906 Compressive Stress (MPa) 410° C. 2 hr Depth of 42 42 45 3843 45 45 Layer (mm) 410° C. 2 hr Vickers >30 >30 >30 >30 >30 >30 >30Crack Initiation Load (kgf) 410° C. 3 hr Compressive Stress (MPa) 410°C. 3 hr Depth of Layer (mm) 410° C. 4 hr Compressive Stress (MPa) 410°C. 4 hr Depth of Layer (mm) 410° C. 4 hr Vickers Crack Initiation Load(kgf) 410° C. 8 hr Compressive Stress (MPa) 410° C. 8 hr Depth of Layer(mm) D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 1 hr DFSM DOL 3.1E−10 3.1E−10 3.6E−10 2.6E−10 3.3E−10 3.6E−10 3.6E−10 ~1.4 *2 * (Dt){circumflex over ( )}0.5 at 410° C. 2 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 3 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 4 hr D FSM DOL ~1.4 * 2 *(Dt){circumflex over ( )}0.5 at 410° C. 8 hr Example Number 142 143 144145 SiO₂ in mol % 57.5 58.1 58.2 58.4 Al₂O₃ in mol % 16.7 16.0 16.0 16.0P₂O₅ in mol % 6.9 6.2 6.2 6.2 Na₂O in mol % 16.7 16.0 16.1 16.1 MgO inmol % 0.1 3.6 3.4 3.1 ZnO in mol % 0.0 0.0 0.0 0.0 SnO₂ in mol % 0.1 0.10.1 0.1 CaO in mol % 2.0 0.1 0.0 0.0 (M₂O₃)/R_(x)O in mol % 0.89 0.810.82 0.83 (P₂O₅ + R₂O)/(M₂O₃) 1.42 1.39 1.40 1.40 in mol % (P₂O₅ +R_(x)O)/(M₂O₃) 1.54 1.62 1.61 1.59 in mol % SiO₂ in wt % 47.3 48.8 48.949.0 Al₂O₃ in wt % 23.3 22.8 22.8 22.8 P₂O₅ in wt % 13.5 12.4 12.3 12.3Na₂O in wt % 14.2 13.9 14.0 14.0 MgO in wt % 0.1 2.0 1.9 1.7 ZnO in wt %0.0 0.0 0.0 0.0 SnO₂ in wt % 0.2 0.1 0.1 0.1 CaO in wt % 1.5 0.0 0.0 0.0Compositional XRF XRF XRF XRF analysis Density (g/cm³) 2.425 2.422 2.4212.418 Molar Volume 30.12 29.52 29.54 29.61 (cm³/mol) Strain Pt. (° C.)615 621 619 616 Anneal Pt. (° C.) 669 672 671 670 Softening Pt. (° C.)930.1 938.5 938.9 941.3 Temperature at 200 P 1655 1652 1662 1664Viscosity (° C.) Temperature at 35 kP 1232 1232 1240 1243 Viscosity (°C.) Temperature at 160 1147 1148 1157 1159 kP Viscosity (° C.) LiquidusTemperature (° C.) Liquidus Viscosity (P) Zircon Breakdown Temperature(° C.) Zircon Breakdown Viscosity (P) Stress Optical Coefficient ((nm ·Mpa⁻¹ · mm⁻¹) Approximate Fictive 750 765 772 770 temperature (° C.)410° C. 1 hr Compressive Stress (MPa) 410° C. 1 hr Depth of Layer (mm)410° C. 1 hr Vickers Crack Initiation Load (kgf) 410° C. 2 hr 902 961953 948 Compressive Stress (MPa) 410° C. 2 hr Depth of 48 40 42 41 Layer(mm) 410° C. 2 hr Vickers >30 >30 >30 >30 Crack Initiation Load (kgf)410° C. 3 hr Compressive Stress (MPa) 410° C. 3 hr Depth of Layer (mm)410° C. 4 hr Compressive Stress (MPa) 410° C. 4 hr Depth of Layer (mm)410° C. 4 hr Vickers Crack Initiation Load (kgf) 410° C. 8 hrCompressive Stress (MPa) 410° C. 8 hr Depth of Layer (mm) D FSM DOL~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 1 hr D FSM DOL4.1E−10 2.8E−10 3.1E−10 3.0E−10 ~1.4 * 2 * (Dt){circumflex over ( )}0.5at 410° C. 2 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at410° C. 3 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410°C. 4 hr D FSM DOL ~1.4 * 2 * (Dt){circumflex over ( )}0.5 at 410° C. 8hr

Ion exchange is widely used to chemically strengthen glass articles foruse in in consumer electronics, automotive applications, appliances,architectural components, and other areas where high levels of damageresistance are desirable. In the ion exchange process, a glass articlecontaining a first metal ion (e.g., alkali cations in Li₂O, Na₂O, etc.)is at least partially immersed in or otherwise contacted with an ionexchange bath or medium containing a second metal ion that is eitherlarger or smaller than the first metal ion that is present in the glass.The first metal ions diffuse from the glass surface into the ionexchange bath/medium while the second metal ions from the ion exchangebath/medium replace the first metal ions in the glass to a depth oflayer below the surface of the glass. The substitution of larger ionsfor smaller ions in the glass creates a compressive stress at the glasssurface, whereas substitution of smaller ions for larger ions in theglass typically creates a tensile stress at the surface of the glass. Insome embodiments, the first metal ion and second metal ion aremonovalent alkali metal ions. However, other monovalent metal ions suchas Ag⁺, Tl⁺, Cu⁺, and the like may also be used in the ion exchangeprocess. In those instances where at least one of Ag⁺ and Cu⁺ isexchanged for metal ions in the glass, such glasses may be particularlyuseful for anti-viral and/or anti-microbial applications.

A cross-sectional view of a portion (i.e., ends of the glass sheet arenot shown) of a glass sheet strengthened by ion exchange isschematically shown in FIG. 1. In the non-limiting example shown in FIG.1, strengthened glass sheet 100 has a thickness t, central portion 130,and a first surface 110 and second surface 112 that are substantiallyparallel to each other. Compressive layers 120, 122 extend from firstsurface 110 and second surface 112, respectively, to depths of layer d₁,d₂ below each surface. Compressive layers 120, 122 are under acompressive stress, while central portion 130 is under a tensile stress,or in tension. The tensile stress in central portion 130 balances thecompressive stresses in compressive layers 120, 122, thus maintainingequilibrium within strengthened glass sheet 100. In some embodiments,the glasses and glass articles described herein may be ion exchanged toachieve a compressive stress of at least about 300 MPa and/or a depth ofcompressive layer of at least about 10 μm. In some embodiments, theglasses and glass articles described herein may be ion exchanged toachieve a compressive stress of at least about 500 MPa and/or a depth ofcompressive layer of at least about 40 μm. In some embodiments, theglass is ion exchanged to achieve a compressive stress of at least about200, 300, 400, 500, 600, 700, 800, 900, or 1000 MPa. In someembodiments, the glass is ion exchanged to achieve a depth of layer ofat least about 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm,90 μm, 100 μm, or 110 μm or more.

In addition to high damage resistance, the glasses described herein maybe ion exchanged to achieve desired levels of compressive stress andcompressive depth of layer in relatively short times. Following ionexchange at 410° C. for 4 hours in molten KNO₃ salt, for example, acompressive layer having a compressive stress of greater than about 700MPa and a depth of compressive layer of greater than about 75 μm may beachieved in these glasses. In some embodiments, the ion exchange is doneat about 400° C., 410° C., 420° C., 430° C., 440° C., 450° C., 460° C.,470° C., 480° C., 490° C., 500° C., 510° C., 520° C., 530° C., 540° C.,or 550° C. or greater. In some embodiments, the ion exchange is done forabout 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10 hours.

FIG. 2 is a plot of depth of layer as a function of compressive stressfor samples a-f in Table 1. The 0.7 mm thick samples were annealed at700° C. and ion exchanged in a molten KNO₃ salt bath at 410° C. fortimes ranging from 1 hour up to 8 hours (groups “b-d” in FIG. 2) or at470° C. for six minutes (group “a” in FIG. 2). The samples that were ionexchanged at 470° C. for six minutes exhibited compressive stresses anddepths of layer that are well below the frangibility limit (i.e., thepoint at which the glass sample should or is likely to exhibit frangiblebehavior, indicated by line 1 in FIG. 2). The ion exchange time requiredfor 0.7 mm thick samples to reach the frangibility limit is slightlygreater than one hour at 410° C. In samples having higher fictivetemperatures with viscosities corresponding to about 10¹¹ Poise (i.e.,unannealed, as down-drawn samples), the frangibility limit will also bemet in a similarly short time, but the compressive stress will be lowerand the depth of layer will be greater than in annealed samples. Samplesthat were ion exchanged for one hour (group “b”) exhibited compressivestresses and depths of layer that are just below the frangibility limit,and samples that were ion exchanged for either 4 or 8 hours (groups “c”and “d”, respectively) exhibit compressive stresses and depths of layerthat exceed the frangibility limit.

The ability to ion exchange the glasses described herein may be at leastpartially attributable to the fact that these glasses have potassium andsodium interdiffusion coefficients that are significantly greater thatthose of other alkali aluminosilicate glasses that are used inapplications in which damage resistance, as characterized by the Vickerscrack initiation threshold of the glass, is a desirable attribute. At410° C., the glasses described herein have a potassium/sodiuminterdiffusion coefficient of at least about 2.4×10⁻¹⁰ cm²/s, 3.0×10⁻¹⁰cm²/s, 4.0×10⁻¹⁰ cm²/s, or 4.5×10⁻¹⁰ cm²/s, 6.0×10⁻¹⁰ cm²/s, 7.5×10⁻¹⁰cm²/s, 9.0×10⁻¹⁰ cm²/s, 1.0×10⁻⁹ cm²/s, 1.2×10⁻⁹ cm²/s, 1.5×10⁻⁹ cm²/sand in some embodiments, in a range from about 2.4×10⁻¹⁰ cm⁻²/s,3.0×10⁻¹⁰ cm²/s, 4.0×10⁻¹⁰ cm²/s, or 4.5×10⁻¹⁰ cm²/s up to about7.5×10⁻¹⁰ cm²/s, 9.0×10⁻¹⁰ cm²/s, 1.0×10⁻⁹ cm²/s, 1.2×10⁻⁹ cm²/s, or1.5×10⁻⁹ cm²/s. In contrast to these glasses, the alkali aluminosilicateglasses described in U.S. patent application Ser. Nos. 12/858,490,12/856,840, and 12/392,577 have potassium/sodium interdiffusioncoefficients of less than 1.5×10⁻¹⁰ cm²/s.

An embodiment comprises an alkali aluminosilicate glass comprising atleast about 4 mol % P₂O₅, wherein [M₂O₃ (mol %)/R_(x)O(mol %)]<1.4,where M₂O₃═Al₂O₃+B₂O₃ and R_(x)O is the sum of monovalent and divalentcation oxides present in the alkali aluminosilicate glass. In someembodiments, [M₂O₃ (mol %)/R_(x)O(mol %)]<1. In some embodiments, thealkali aluminosilicate glass further comprises less than 1 mol % K₂O. Insome embodiments, the alkali aluminosilicate glass comprises 0 mol %K₂O. In some embodiments, the alkali aluminosilicate glass comprisesless than 1 mol % B₂O₃. In some embodiments, the alkali aluminosilicateglass comprises 0 mol % B₂O₃. In some embodiments, the monovalent anddivalent cation oxides are selected from the group consisting of Li₂O,Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO. In some embodiments,the alkali aluminosilicate glass has a potassium/sodium interdiffusioncoefficient of at least about 2.4×10⁻¹⁰ cm²/s at 410° C. In someembodiments, the potassium/sodium interdiffusion coefficient is in arange from about 2.4×10⁻¹⁰ cm²/s up to about 1.5×10⁻⁹ cm²/s at 410° C.

An embodiment comprises an alkali aluminosilicate glass comprising0.6<[M₂O₃ (mol %)/R_(x)O(mol %)]<1.4 where M₂O₃═Al₂O₃+B₂O₃ and R_(x)O isthe sum of monovalent and divalent cation oxides present in the alkalialuminosilicate glass. In some embodiments, 0.8<[M₂O₃(mol %)/R_(x)O(mol%)]<1.4. In some embodiments, 0.8≦[M₂O₃(mol %)/R_(x)O(mol %)]≦1.0. Insome embodiments, the alkali aluminosilicate glass further comprisesless than 1 mol % K₂O. In some embodiments, the alkali aluminosilicateglass comprises 0 mol % K₂O. In some embodiments, the alkalialuminosilicate glass comprises less than 1 mol % B₂O₃. In someembodiments, the alkali aluminosilicate glass comprises 0 mol % B₂O₃. Insome embodiments, the monovalent and divalent cation oxides are selectedfrom the group consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO,BaO, and ZnO. In some embodiments, the alkali aluminosilicate glass hasa potassium/sodium interdiffusion coefficient of at least about2.4×10⁻¹⁰ cm²/s at 410° C. In some embodiments, the potassium/sodiuminterdiffusion coefficient is in a range from about 2.4×10⁻¹⁰ cm²/s upto about 1.5×10⁻⁹ cm²/s at 410° C.

Another embodiment comprises an alkali aluminosilicate glass comprisingat least about 4% P₂O₅, wherein the alkali aluminosilicate glass is ionexchanged to a depth of layer of at least about 20 μm, and wherein0.6<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4, where M₂O₃═Al₂O₃+B₂O₃ and R_(x)O isthe sum of monovalent and divalent cation oxides present in the alkalialuminosilicate glass. In some embodiments, 0.6<[M₂O₃(mol %)/R_(x)O(mol%)]<1.0. In some embodiments, 0.8<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4. Insome embodiments, 0.8≦[M₂O₃(mol %)/R_(x)O(mol %)]≦1.0. In someembodiments, the alkali aluminosilicate glass further comprises lessthan 1 mol % K₂O. In some embodiments, the alkali aluminosilicate glasscomprises 0 mol % K₂O. In some embodiments, the alkali aluminosilicateglass comprises less than 1 mol % B₂O₃. In some embodiments, the alkalialuminosilicate glass comprises 0 mol % B₂O₃. In some embodiments, themonovalent and divalent cation oxides are selected from the groupconsisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO.In some embodiments, the alkali aluminosilicate glass has apotassium/sodium interdiffusion coefficient of at least about 2.4×10⁻¹⁰cm²/s at 410° C. In some embodiments, the potassium/sodiuminterdiffusion coefficient is in a range from about 2.4×10⁻¹⁰ cm²/s upto about 1.5×10⁻⁹ cm²/s at 410° C.

Another embodiment comprises an alkali aluminosilicate glass comprisingat least about 4% P₂O₅, wherein 1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3, whereM₂O₃═Al₂O₃+B₂O₃ and R₂O is the sum of monovalent cation oxides presentin the alkali aluminosilicate glass. In some embodiments, the alkalialuminosilicate glass further comprises less than 1 mol % K₂O. In someembodiments, the alkali aluminosilicate glass comprises 0 mol % K₂O. Insome embodiments, the alkali aluminosilicate glass comprises less than 1mol % B₂O₃. In some embodiments, the alkali aluminosilicate glasscomprises 0 mol % B₂O₃. In some embodiments, the monovalent and divalentcation oxides are selected from the group consisting of Li₂O, Na₂O, K₂O,Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, and ZnO. In some embodiments, the alkalialuminosilicate glass has a potassium/sodium interdiffusion coefficientof at least about 2.4×10⁻¹⁰ cm²/s at 410° C. In some embodiments, thepotassium/sodium interdiffusion coefficient is in a range from about2.4×10⁻¹⁰ cm²/s up to about 1.5×10⁻⁹ cm²/s at 410° C.

In some embodiments, the alkali aluminosilicate glass comprises fromabout 40 mol % to about 70 mol % SiO₂; from about 11 mol % to about 25mol % Al₂O₃; from about 4 mol % to about 15 mol % P₂O₅; and from about13 mol % to about 25 mol % Na₂O. In some embodiments, the alkalialuminosilicate glass comprises from about 50 mol % to about 65 mol %SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4 mol % toabout 10 mol % P₂O₅; and from about 14 mol % to about 20 mol % Na₂O. Insome embodiments, the alkali aluminosilicate glass further comprisesless than 1 mol % K₂O. In some embodiments, the alkali aluminosilicateglass comprises 0 mol % K₂O. In some embodiments, the alkalialuminosilicate glass comprises less than 1 mol % B₂O₃. In someembodiments, the alkali aluminosilicate glass comprises 0 mol % B₂O₃. Insome embodiments, the monovalent and divalent cation oxides are selectedfrom the group consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO,BaO, and ZnO.

In some embodiments, the alkali aluminosilicate glasses described aboveare ion exchanged to a depth of layer of at least about 20 μm. In someembodiments, the glasses are ion exchanged to a depth of layer of atleast about 40 μm. In some embodiments, the alkali aluminosilicateglasses have a compressive layer extending from a surface of the glassto the depth of layer, and wherein the compressive layer is under acompressive stress of at least 500 MPa. In some embodiments, thecompressive stress is at least 750 MPa. In some embodiments, thecompressive stress layer is from about 500 MPa to about 2000 MPa. Insome embodiments, the ion exchanged alkali aluminosilicate glasses havea Vickers indentation crack initiation load of at least about 8 kgf. Insome embodiments, the ion exchanged alkali aluminosilicate glasses havea Vickers indentation crack initiation load of at least about 12 kgf.

An embodiment comprises a method of strengthening an alkalialuminosilicate glass, the method comprising: providing an alkalialuminosilicate glass as described above, and immersing the alkalialuminosilicate glass in an ion exchange bath for a time period of up toabout 24 hours to form a compressive layer extending from a surface ofthe alkali aluminosilicate glass to a depth of layer of at least 20 μm.In some embodiments, the alkali aluminosilicate glass comprises at leastabout 4 mol % P₂O₅, wherein [M₂O₃ (mol %)/R_(x)O(mol %)]<1.4, whereM₂O₃═Al₂O₃+B₂O₃ and R_(x)O is the sum of monovalent and divalent cationoxides present in the alkali aluminosilicate glass. In some embodiments,[M₂O₃ (mol %)/R_(x)O(mol %)]<1. In some embodiments, the alkalialuminosilicate glass comprises 0.6<[M₂O₃ (mol %)/R_(x)O(mol %)]<1.4where M₂O₃═Al₂O₃+B₂O₃ and R_(x)O is the sum of monovalent and divalentcation oxides present in the alkali aluminosilicate glass. In someembodiments, 0.8<[M₂O₃(mol %)/R_(x)O(mol %)]<1.4. In some embodiments,0.8≦[M₂O₃(mol %)/R_(x)O(mol %)]≦1.0. In some embodiments, the alkalialuminosilicate glass comprising at least about 4% P₂O₅, wherein1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3, where M₂O₃═Al₂O₃+B₂O₃ and R₂O is the sum ofmonovalent cation oxides present in the alkali aluminosilicate glass. Insome embodiments, the alkali aluminosilicate glass comprises from about40 mol % to about 70 mol % SiO₂; from about 11 mol % to about 25 mol %Al₂O₃; from about 4 mol % to about 15 mol % P₂O₅; and from about 13 mol% to about 25 mol % Na₂O. In some embodiments, the alkalialuminosilicate glass comprises from about 50 mol % to about 65 mol %SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4 mol % toabout 10 mol % P₂O₅; and from about 14 mol % to about 20 mol % Na₂O. Insome embodiments, the alkali aluminosilicate glass further comprisesless than 1 mol % K₂O. In some embodiments, the alkali aluminosilicateglass comprises 0 mol % K₂O. In some embodiments, the alkalialuminosilicate glass comprises less than 1 mol % B₂O₃. In someembodiments, the alkali aluminosilicate glass comprises 0 mol % B₂O₃. Insome embodiments, the monovalent and divalent cation oxides are selectedfrom the group consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO,BaO, and ZnO.

In some embodiments, the alkali aluminosilicate glasses described aboveare ion exchanged to a depth of layer of at least about 20 μm. In someembodiments, the glasses are ion exchanged to a depth of layer of atleast about 40 μm. In some embodiments, the alkali aluminosilicateglasses have a compressive layer extending from a surface of the glassto the depth of layer, and wherein the compressive layer is under acompressive stress of at least 500 MPa. In some embodiments, thecompressive stress is at least 750 MPa. In some embodiments, thecompressive stress layer is from about 500 MPa to about 2000 MPa. Insome embodiments, the ion exchanged alkali aluminosilicate glasses havea Vickers indentation crack initiation load of at least about 8 kgf. Insome embodiments, the ion exchanged alkali aluminosilicate glasses havea Vickers indentation crack initiation load of at least about 12 kgf.

While typical embodiments have been set forth for the purpose ofillustration, the foregoing description should not be deemed to be alimitation on the scope of the disclosure or appended claims.Accordingly, various modifications, adaptations, and alternatives mayoccur to one skilled in the art without departing from the spirit andscope of the present disclosure or appended claims.

1. An alkali aluminosilicate glass comprising at least about 4% P₂O₅,wherein:[M₂O₃(mol%)/R_(x)O(mol%)]<1.4; or  i.1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3;  ii. where M₂O₃═Al₂O₃+B₂O₃, R_(x)O is the sumof monovalent and divalent cation oxides present in the alkalialuminosilicate glass, and R₂O is the sum of divalent cation oxidespresent in the alkali aluminosilicate glass.
 2. The alkalialuminosilicate glass of claim 1, wherein the glass satisfies:[M₂O₃(mol%)/R_(x)O(mol%)]<1.4.
 3. The alkali aluminosilicate glass ofclaim 2, wherein the glass satisfies:[M₂O₃(mol%)/R_(x)O(mol%)]<1.
 4. The alkali aluminosilicate glass ofclaim 1, wherein the glass satisfies:1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3.
 5. The alkali aluminosilicate glass of claim4, wherein the glass satisfies:1.5<[(P₂O₅+R₂O)/M₂O₃]≦2.0.
 6. The alkali aluminosilicate glass of claim1, further comprising less than 1 mol % K₂O.
 7. The alkalialuminosilicate glass of claim 6, wherein the alkali aluminosilicateglass comprises 0 mol % K₂O.
 8. The alkali aluminosilicate glass ofclaim 1, further comprising less than 1 mol % B₂O₃.
 9. The alkalialuminosilicate glass of claim 8, wherein the alkali aluminosilicateglass comprises 0 mol % B₂O₃.
 10. The alkali aluminosilicate glass ofclaim 1, wherein the glass is ion exchanged to a depth of layer of atleast about 10 μm.
 11. The alkali aluminosilicate glass of claim 10,wherein the glass is ion exchanged to a depth of layer of at least about30 μm.
 12. The alkali aluminosilicate glass of claim 10, wherein thealkali aluminosilicate glass has a compressive layer extending from asurface of the glass to the depth of layer, and wherein the compressivelayer is under a compressive stress of at least about 300 MPa.
 13. Thealkali aluminosilicate glass of claim 12, wherein the compressive stressis at least about 500 MPa.
 14. The alkali aluminosilicate glass of claim10, wherein the ion exchanged alkali aluminosilicate glass has a Vickersindentation crack initiation load of at least about 7 kgf.
 15. Thealkali aluminosilicate glass of claim 14, wherein the ion exchangedalkali aluminosilicate glass has a Vickers indentation crack initiationload of at least about 12 kgf.
 16. The alkali aluminosilicate glass ofclaim 1, wherein the monovalent and divalent cation oxides are selectedfrom the group consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO,BaO, and ZnO.
 17. The alkali aluminosilicate glass of claim 1, whereinthe alkali aluminosilicate glass comprises from about 40 mol % to about70 mol % SiO₂; from about 11 mol % to about 25 mol % Al₂O₃; from about 4mol % to about 15 mol % P₂O₅; and from about 13 mol % to about 25 mol %Na₂O.
 18. The alkali aluminosilicate glass of claim 17, wherein thealkali aluminosilicate glass comprises from about 50 mol % to about 65mol % SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4mol % to about 10 mol % P₂O₅; and from about 14 mol % to about 20 mol %Na₂O.
 19. The alkali aluminosilicate glass of claim 17, wherein thealkali aluminosilicate glass further comprises less than 1 mol % K₂O.20. The alkali aluminosilicate glass of claim 19, wherein the alkalialuminosilicate glass comprises 0 mol % K₂O.
 21. The alkalialuminosilicate glass of claim 17, wherein the alkali aluminosilicateglass further comprises less than 1 mol % B₂O₃.
 22. The alkalialuminosilicate glass of claim 19, wherein the alkali aluminosilicateglass comprises 0 mol % B₂O₃.
 23. The alkali aluminosilicate glass ofclaim 1, wherein the alkali aluminosilicate glass has a potassium/sodiuminterdiffusion coefficient of at least about 2.4×10⁻¹⁰ cm²/s at 410° C.24. The alkali aluminosilicate glass of claim 23, wherein thepotassium/sodium interdiffusion coefficient is in a range from about2.4×10⁻¹⁰ cm²/s up to about 1.5×10⁻⁹ cm²/s at 410° C.
 25. The alkalialuminosilicate glass of claim 1, wherein the glass satisfies:0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4.
 26. An alkali aluminosilicate glasscomprising at least about 4% P₂O₅, wherein the alkali aluminosilicateglass is ion exchanged to a depth of layer of at least about 10 μm, andwherein:0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4; or  i.1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3;  ii. where M₂O₃═Al₂O₃+B₂O₃, R_(x)O is the sumof monovalent and divalent cation oxides present in the alkalialuminosilicate glass, and R₂O is the sum of divalent cation oxidespresent in the alkali aluminosilicate glass.
 27. The alkalialuminosilicate glass of claim 26, wherein the glass satisfies:0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4.
 28. The alkali aluminosilicate glassof claim 27, wherein the glass satisfies:0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.
 29. The alkali aluminosilicate glass ofclaim 26, wherein the glass satisfies:1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3.
 30. The alkali aluminosilicate glass of claim29, wherein the glass satisfies:1.5<[(P₂O₅+R₂O)/M₂O₃]≦2.0.
 31. The alkali aluminosilicate glass of claim26, further comprising less than 1 mol % K₂O.
 32. The alkalialuminosilicate glass of claim 26, further comprising less than 1 mol %B₂O₃.
 33. The alkali aluminosilicate glass of claim 26, wherein thealkali aluminosilicate glass has a potassium/sodium interdiffusioncoefficient of at least about 2.4×10⁻¹⁰ cm²/s at 410° C.
 34. The alkalialuminosilicate glass of claim 33, wherein the potassium/sodiuminterdiffusion coefficient is in a range from about 2.4×10⁻¹⁰ cm²/s upto about 1.5×10⁻⁹ cm²/s at 410° C.
 35. The alkali aluminosilicate glassof claim 26, wherein the glass has a compressive layer extending from asurface of the glass to the depth of layer, and wherein the compressivelayer is under a compressive stress of at least about 300 MPa.
 36. Thealkali aluminosilicate glass of claim 26, wherein the ion exchangedglass has a Vickers indentation crack initiation load of at least about7 kgf.
 37. The alkali aluminosilicate glass of claim 36, wherein the ionexchanged glass has a Vickers indentation crack initiation load of atleast about 12 kgf.
 38. The alkali aluminosilicate glass of claim 1,wherein the monovalent and divalent cation oxides are selected from thegroup consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, MgO, CaO, SrO, BaO, andZnO.
 39. The alkali aluminosilicate glass of claim 1, wherein the alkalialuminosilicate glass comprises from about 40 mol % to about 70 mol %SiO₂; from about 11 mol % to about 25 mol % Al₂O₃; from about 4 mol % toabout 15 mol % P₂O₅; and from about 13 mol % to about 25 mol % Na₂O. 40.The alkali aluminosilicate glass of claim 14, wherein the alkalialuminosilicate glass comprises from about 50 mol % to about 65 mol %SiO₂; from about 14 mol % to about 20 mol % Al₂O₃; from about 4 mol % toabout 10 mol % P₂O₅; and from about 14 mol % to about 20 mol % Na₂O. 41.The alkali aluminosilicate glass of claim 14, wherein the alkalialuminosilicate glass further comprises less than 1 mol % K₂O.
 42. Thealkali aluminosilicate glass of claim 14, wherein the alkalialuminosilicate glass further comprises less than 1 mol % B₂O₃.
 43. Thealkali aluminosilicate glass of claim 14, wherein the potassium/sodiuminterdiffusion coefficient is in a range from about 2.4×10⁻¹⁰ cm²/s upto about 1.5×10⁻⁹ cm²/s at 410° C.
 44. A method of strengthening analkali aluminosilicate glass, the method comprising: a. providing thealkali aluminosilicate glass of claim 1 or claim 26, and b. immersingthe alkali aluminosilicate glass in an ion exchange bath for a timeperiod of up to about 24 hours to form a compressive layer extendingfrom a surface of the alkali aluminosilicate glass to a depth of layerof at least 10 nm.
 45. The method of claim 44, wherein the glasssatisfies:[M₂O₃(mol%)/R_(x)O(mol%)]<1.4.
 46. The method of claim 44, wherein theglass satisfies:[M₂O₃(mol%)/R_(x)O(mol%)]<1.
 47. The method of claim 44, wherein theglass satisfies:0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.4.
 48. The method of claim 44, whereinthe glass satisfies:0.6<[M₂O₃(mol%)/R_(x)O(mol%)]<1.
 49. The method of claim 44, wherein theglass satisfies:1.3<[(P₂O₅+R₂O)/M₂O₃]≦2.3.
 50. The method of claim 44, wherein the glasssatisfies:1.5<[(P₂O₅+R₂O)/M₂O₃]≦2.0.
 51. The method of claim 44, wherein thealkali aluminosilicate glass comprises less than 1 mol % K₂O.
 52. Themethod of claim 44, wherein the alkali aluminosilicate glass comprisesless than 1 mol % B₂O₃.
 53. The method of claim 44, wherein thecompressive layer is under a compressive stress of at least about 300MPa.
 54. The method of claim 44, wherein the ion exchanged glass has aVickers indentation crack initiation load of at least about 7 kgf. 55.The method of claim 44, wherein the ion exchanged glass has a Vickersindentation crack initiation load of at least about 12 kgf.